fixed test failure on CPU 1 core machine.

gzip: added Vary: Accept-Encoding to response header.

When CPU is 1 core, expected value (int(0.5 * float32(maxCPU))) is zero.
But runtime.GOMAXPROCS(-1) returns always 1.

When the downstream is cache server or CDN, it is important.

startup: Only run commands at first startup

Actually, restart on posix systems failed entirely if caddy was executed without the path included; also fixed a related bug where a variable was declared but never assigned.

We had to hack some special support into the server and caddy packages for this. There are some middlewares which should only execute commands when the original parent process first starts up. For example, someone using the startup directive to start a backend service would not expect the command to be executed every time the config was reloaded or changed - only once when they first started the original caddy process.

This commit adds FirstStartup to the virtualhost config

Alphabetize command line options, add -pidfile

As per https://github.com/mholt/caddy/issues/331

As per https://github.com/mholt/caddy/issues/317

Some programs (Node.js, supervisor, etc.) open a stdin pipe by default and don't use it, causing Caddy to block. It is their error, but we have to try to accommodate unfortunately. To fix this more universally, parent must explicitly set -conf to "stdin" to read from pipe.

Since a directive can appear on multiple lines, the object syntax wasn't working well. This also fixes several other serialization bugs.

The error channel used when starting all the servers must be buffered so that, even if there are no errors at startup, the returns that insert into the error channel will not be blocked, since after startup, nobody is reading that channel anymore.

Wrote tests for browse.go and redir.go

The base path being optional in the Caddyfile is convenient when you just want the whole site to be markdown-enabled. The other change is to always generate links... this is because an index page for markdown files may not be statically generated, but it should still show links. Commit 09341fca was a regression, and this fixes it.

It can take a few seconds...

use log instead of fmt to obey the -log flag

fixed data races in websockets

Also we're not messing with log flags anymore during parsing. Timestamps could come in handy, plus concurrent logging is going on now.

Previously, if a listener fails to bind (for example), there was a race in caddy.go between unblocking the startup waitgroup and returning the error and putting it into errChan. Now, an error is returned directly into errChan and the closing of the startup waitgroup is defered until after that return takes place.

Log file can also be stdout or stderr. Log output is disabled by default now, which makes it more feasible to add more log statements to trace program flow in debugging situations.

add helpful suggestion to identify problem

This is known to happen if another program spawns Caddy with a stdin pipe but does not close its write end of Caddy's stdin.

Lint pacification