startup and shutdown commands should only be executed once per appearance in the Caddyfile (naturally meaning once per server block).

Notice that we support multiple occurrences of startup and shutdown in the same server block by building the callback array incrementally as we parse the Caddyfile, then we append all the callbacks all at once. Quite literally, the OncePerServerBlock function executes only once per server block!

If each server block had only one sync.Once then all directives would refer to it and only the first directive would be able to use it! So this commit changes it to a map of sync.Once instances, keyed by directive. So by creating a new map for every server block, each directive in that block can get its own sync.Once which is exactly what is needed. They won't step on each other this way.

Turns out having each server block share a single server.Config during initialization when the Setup functions are being called was a bad idea. Sure, startup and shutdown functions were only executed once, but they had no idea what their hostname or port was. So here we revert to the old way of doing things where Setup may be called multiple times per server block (once per host associated with the block, to be precise), but the Setup functions now know their host and port since the config belongs to exactly one virtualHost. To have something happen just once per server block, use OncePerServerBlock, a new function available on each Controller.

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 '/'.