Merge pull request apiaryio#77 from apiaryio/develop 1A4

Merge pull request apiaryio#64 from apiaryio/1A 1A revision 3: Deprecate resource & action level headers

Merge pull request apiaryio#56 from apiaryio/1A Format 1A Revision 2

Add ga-beacon analytics pixel 

Add ga-beacon analytics pixel 

Add ga-beacon analytics pixel