markdown, browse: Integrated Context struct for templating

Put the title into the .Doc variables as well.
Changed the test template file to use new names.

This is a breaking change for those who expect catch-all redirects to preserve path; use {uri} variable explicitly now

browse: Save sorting preferences as cookies

To be used across directories

Changed the tests accordingly.

initial test for config/setup/fastcgi.go

Created a struct containing middleware.Context, Title, Markdown and the
variables from the user to use to render the template.
The title now can be accessed via {{.Title}}.
The variables can now be accessed via {{.Var.myVariableName}}.

specify go versions to use via travis

Created sample files for the test

Moved the Context type to middleware and exported it.
Users can use .Include and others in browse directive templating
Created test for the templates directive.

redir: Preserve query string on catch-all redirect (fixes #180)

Use path.Join and then check if the request had a slash at the end to
place it again.

Used http status code instead of a hardcoded value.
Used url.Parse instead of url.ParseRequestURI, so that you can parse
both absolute and relative URL.

The get parameters are now forwarded when redirected.
Added some tests to validate this behavior.

Complete test coverage for config/setup/markdown.go

ext: Initial tests for the extensions middleware

gzip: Const for wildcard extension (and added test)