docs(ngClass): Explain all 3 ways how to use ngClass

Closes #6324.
fix(jqLite): make jqLite('<iframe src="someurl">').contents() return iframe document, as in jQuery

This is a very tiny change to make behaviour consistent with jQuery.

Closes #6320
Closes #6323
style(jqLite): remove trailing whitespace in new test

Oops.
chore(travis): don't run Travis-CI builds for G3 branches

Building the G3 commits occupies a lot of time, and these branches have
already been tested.

Closes #6328
docs(guide/providers): fix example snippet

Closes #6331
Closes #6332
docs(triaging): remove reference to the obsolete chrome extension
docs(contributing): remove reference to the obsolete chrome extension
docs($routeProvider): fix indentation

Closes #6345

Somebody accidentally padded a list with one-too-many indentations, which caused the actual documentation page to render incorrectly. This should fix it.
chore(doc-app): remove invalid line of code
chore(doc-gen): improve grouping and sorting of api nav items
docs(api): remove ngRoute.$routeParams link from ng section

Closes #6219
fix(ngRoute): remove extra decodeURIComponent

Since `$location.$$path` is already decoded, doing an extra `decodeURIComponent` is both unnecessary and can cause problems. Specifically, if the path originally included an encoded `%` (aka `%25`), then ngRoute will throw "URIError: URI malformed".

Closes #6326