Ensure static query params are being appended properly.

Closes #212.
Merge pull request #215 from square/jw/static-query

Ensure static query params are being appended properly.
Don't send null query values
Add @Endpoint to specify explicit endpoints
Parse endpoint in parseParams instead
Fix appendage of query parameters to explicitly-set endpoints
Added custom query parameter serializers
Allow other serializers too...
Expose ApacheClient.client so it AndroidApacheClient can close() it
Merge branch 'master' of github.com:johnsto/retrofit

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