Per issue #12. Adding initial implementation of listing the countries.
Per issue #12. Error messaging.
Per issue #12. Adding some asserts into the test.
Per issue #12. Parsing the countries too.
Merge branch 'develop' into list_competitions

Conflicts:
	BNGAPI/BNGAPI.xcodeproj/project.pbxproj
	BNGAPI/BNGAPI/Classes/BNGAPIResponseParser.h
	BNGAPI/BNGAPI/Classes/BNGAPIResponseParser.m