Basic unittest structure
Move src files into Proxy subdirectory
Unittests for the masses
Rebase aftermath
Merge pull request #5 from rebuy-de/unittests

Unittests
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/Adapter/Adapter.php
	src/Adapter/AdapterInterface.php
	src/Proxy/Adapter/Adapter.php
	src/Proxy/Adapter/Guzzle/GuzzleAdapter.php
	src/Proxy/Request/Filter/RequestFilter.php
	src/Proxy/Response/Filter/RemoveEncodingFilter.php
	src/Proxy/Response/Filter/ResponseFilter.php
	src/Request/Filter/RequestFilter.php
	src/Request/Filter/RequestFilterInterface.php
	src/Response/Filter/ResponseFilter.php
	src/Response/Filter/ResponseFilterInterface.php
Small code touchup
Merge branch 'rebuy-de-master'
Merging PR #15 and adding Travis