gh-47 Add test overriding default language via system property

Conflicts:
	.gitignore
Correct Http test assertion and add coordination with handler completion
Define HTTP tests in base class and extend
gh-155 Fix HTTP CONNECT test expectations and adjust scaladoc
gh-172 Fix module location for compilation on Windows

* Using toExternalForm on URL produces a UNIX-style path which does
not work fine on Windows machines. Instead, create a File with the
URL's URI and get absolute path for it, which produces a plattform
dependant path.