docs(guide/forms): clarify how NgModelController can be added to scope

Closes #5200
docs(tutorial): enlarge clickable area of tutorial nav buttons

Change position of <a> and <li> tags in tutorial nav buttons
partial. This allows the full area of the button to be clicked
rather than just the text.

Closes #5074
Closes #5209
docs(contribute) add platform agnostic git install link

Closes #5216
docs($q): correct typo in the 'Differences Q/$q' section

Closes #5230
docs($route): clarify examples of route parameters

Putting route parameter examples in braces was misleading newcomers.

Closes #5243
docs(input): remove redundant closing span tag

Closes #5257
Merge branch 'master' of https://github.com/angular/angular.js
componentizd!