proxy: add Host header checking

dist/init/linux-sysvinit: execute setcap directly

`$(which setcap)` might evaluate to nothing,
and this way the error thrown will be more clear.
If setcap is not available on Debian/Ubuntu,
you can install the package `libcap2-bin`

* dist/init/linux-sysvinit: pass --oknodo for --start as well

* dist/init/linux-sysvinit: manually rm PIDFILE

Since start-stop-daemon --remove-pidfile is new and not present
everywhere.

dist/init/linux-sysvinit: fix minor typo in DAEMONOPTS

fix issue #993
Signed-off-by: Tw <tw19881113@gmail.com>

* improve rlimit usage

* fix windows build

* fix code style

added ip_hash load balancing

tls: fix TestStandaloneTLSTicketKeyRotation data race

==================
WARNING: DATA RACE
Write at 0x00c42049d300 by goroutine 26:
  github.com/mholt/caddy/caddytls.standaloneTLSTicketKeyRotation()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto.go:230 +0x698

Previous read at 0x00c42049d300 by goroutine 25:
  github.com/mholt/caddy/caddytls.TestStandaloneTLSTicketKeyRotation()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto_test.go:113 +0x413
  testing.tRunner()
      /home/tw/goroot/src/testing/testing.go:610 +0xc9

Goroutine 26 (running) created at:
  github.com/mholt/caddy/caddytls.TestStandaloneTLSTicketKeyRotation()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto_test.go:101 +0x2a4
  testing.tRunner()
      /home/tw/goroot/src/testing/testing.go:610 +0xc9

Goroutine 25 (running) created at:
  testing.(*T).Run()
      /home/tw/goroot/src/testing/testing.go:646 +0x52f
  testing.RunTests.func1()
      /home/tw/goroot/src/testing/testing.go:793 +0xb9
  testing.tRunner()
      /home/tw/goroot/src/testing/testing.go:610 +0xc9
  testing.RunTests()
      /home/tw/goroot/src/testing/testing.go:799 +0x4b5
  testing.(*M).Run()
      /home/tw/goroot/src/testing/testing.go:743 +0x12f
  github.com/mholt/caddy/caddytls.TestMain()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/setup_test.go:27 +0x133
  main.main()
      github.com/mholt/caddy/caddytls/_test/_testmain.go:116 +0x1b1
==================
==================
WARNING: DATA RACE
Write at 0x00c4204aa6c0 by goroutine 26:
  github.com/mholt/caddy/caddytls.TestStandaloneTLSTicketKeyRotation.func2()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto_test.go:93 +0x56
  github.com/mholt/caddy/caddytls.standaloneTLSTicketKeyRotation()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto.go:233 +0x638

Previous read at 0x00c4204aa6c0 by goroutine 25:
  github.com/mholt/caddy/caddytls.TestStandaloneTLSTicketKeyRotation()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto_test.go:108 +0x391
  testing.tRunner()
      /home/tw/goroot/src/testing/testing.go:610 +0xc9

Goroutine 26 (running) created at:
  github.com/mholt/caddy/caddytls.TestStandaloneTLSTicketKeyRotation()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/crypto_test.go:101 +0x2a4
  testing.tRunner()
      /home/tw/goroot/src/testing/testing.go:610 +0xc9

Goroutine 25 (running) created at:
  testing.(*T).Run()
      /home/tw/goroot/src/testing/testing.go:646 +0x52f
  testing.RunTests.func1()
      /home/tw/goroot/src/testing/testing.go:793 +0xb9
  testing.tRunner()
      /home/tw/goroot/src/testing/testing.go:610 +0xc9
  testing.RunTests()
      /home/tw/goroot/src/testing/testing.go:799 +0x4b5
  testing.(*M).Run()
      /home/tw/goroot/src/testing/testing.go:743 +0x12f
  github.com/mholt/caddy/caddytls.TestMain()
      /home/tw/golib/src/github.com/mholt/caddy/caddytls/setup_test.go:27 +0x133
  main.main()
      github.com/mholt/caddy/caddytls/_test/_testmain.go:116 +0x1b1
==================
Signed-off-by: Tw <tw19881113@gmail.com>

updated tests

fixed comment format

fixed formatting, minor logic fix

added newline to EOF

updated logic, fixed tests

added comment

updated formatting

updated test output

fixed typo

Re-enable HTTP/2 for Go 1.7.

dist/init/linux-sysvinit: caddy for SysVinit

In addition to `linux-upstart` and `linux-systemd`, I think this one
might be very useful too.

The script is based on [this script](https://git.devuan.org/fredg/stuffs/blob/master/caddy/init.d/caddy)
by @fredg, found via [Installation du serveur Caddy sous Devuan · Frédéric Galusik](http://galusik.xyz/installation-caddy-server-devuan/#démon:d7570338f345f168f3c50f22e7f8c47c).
I have modified it into an extended version myself, since I had the need for this.

redir: loading block arguments before parsing matcher

fix issue #977
Signed-off-by: Tw <tw19881113@gmail.com>

 * Since Go 1.7 HTTP/2 support is enabled only if TLSConfig.NextProtos
   includes the string "h2".
 * see mholt/caddy#975

Specify the reload signal in the upstart script

Change position of locale directive

First, great job on the 0.9 release! It seems caddy's path lead into a bright future. Thanks also for including the locale plugin.

Trying it, I've figured out, that there might be a problem with the order of the directives. In the typical use case, the result of the locale detection might be used in the `rewrite` and `log` plugin. If I'm not mistaken, it makes sense to put the `locale` directive before those.

Register ratelimit

This reverts commit 9ea05919, reversing
changes made to 2125ae5f.

minor condition keyword check refactor

proxy: fix hyphen issue when parsing target

HTTP Headers

fix issue #948
Signed-off-by: Tw <tw19881113@gmail.com>

add a test to ensure this works.

* proxy: add benchmark
Signed-off-by: Tw <tw19881113@gmail.com>

* replacer: prepare lazily

update issue#939

benchmark            old ns/op     new ns/op     delta
BenchmarkProxy-4     83865         72544         -13.50%
Signed-off-by: Tw <tw19881113@gmail.com>

* proxy: use buffer pool to avoid temporary allocation
Signed-off-by: Tw <tw19881113@gmail.com>