docs: add missing priority documentation for structural directives
chore(release): cut 1.2.0-rc.3 ferocious-twitch release
docs(changelog): release notes for 1.2.0-rc.3
chore(release): start 1.2.0 iteration
fix($parse): check function call context to be safe

Closes #4417
docs($rootScope): better document infinite digest and ttl
Merge remote-tracking branch 'upstream/master' into development