added @Raw annotation for retrieving the response without converting to byte[] first (as suggested in #478)
incl. tests
Rename '@Raw' to '@Streaming' for better semantics.

Tests were updated to be more comprehensive and correct.
Merge branch 'raw'
Merge branch 'master' of https://github.com/square/retrofit

Conflicts:
	retrofit/src/test/java/retrofit/RestAdapterTest.java