websocket: Refactored to use gorilla instead of golang/x

Distinguish between windows and linux builds

Ran gofmt -s, fixed some golint warnings, refactored some large functions

Minor quality improvements (closes #253)

Add tests for root.go

... I think. Submitting as PR to double-check. This change changes file mod times on the testdata to ensure they are not all the same so that the sort is predictable!

browse: Better test coverage and fix #264

Exhaustive test coverage to test the usage of sort,order and limit parameter for the browse middleware

browse: allow consecutive spaces in filenames

New core middleware, MIME.

And added tests for status code and scheme

Turns out the stuff in the test file needs to be exported so external add-ons can use them

fastcgi: Stripping PATH_INFO from SCRIPT_NAME

Conflicts:
	middleware/fastcgi/fastcgi.go

core: change to new http2 repo

The golang.org/x/net/http2 is now the official http2 repo.
It is advised to change the imports to it.

Also updated change list and added/improved tests

rewrite: Use middleware.Replacer

Bug fix for regexps starting with '/'.

browse: User defined variables (for templates)