docs($injector): add example on how to use the element.injector

Closes #5188
chore(CHANGELOG): introduce perf() section for performance-related commits

Instead of using fix() or chore() when labelling a commit which improves
speed or performance use perf(). Perf commits will be listed in the
CHANGELOG under "Performance Improvements".

For example:
perf($animate): cache all getComputedStyle operations to reduce additional reflows
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
style($route): make jshint happy

Fix the broken build and earn a late (french spelling).
docs(design): guide index formatting

Just my first pass at a more readable format of the guide index.

Note: the styles apply to all content in the docs, not just the guide
index. This is intentional and I feel that the result is positive.
docs(TRIAGING): Labels cla yes/no are automatically set

The labels are set by a script and
should not be set manually any more.
docs(TRIAGING): Add Type:Perf label
chore(travis): run two jobs

Instead of parallelization on a single Travis VM, we use two VMs.
- output is nicer (we don't have to buffer e2e tests and then show it at the end)
- you can easily see faster the result of unit tests (as it's basically a separate build)

We should also make sure we only do the necesary stuff (for install we don't need to do `grunt
package` for unit tests, we only need to generate the docs for e2e tests.
chore(scripts): refactor travis scripts

Refactoring so that it's easier to use both SL/BS just depending on a global switch.
chore(scripts): fix bower script to pull from master before updating
fix(angular-mocks): use copy of mock data in $httpBackend

Copy mock data returned from the mock $httpBackend.
This prevents modifications to the response from affecting future responses.
Previously, this misbehavior was being mitigated by the deep copy in $resource, but that no longer exists.
docs(error/transclude/orphan): fix spelling mistakes

Closes #5259
docs(ng.$rootScope.Scope): fix API links

Also added a note to the Writing AngularJS Documentation:
https://github.com/angular/angular.js/wiki/Writing-AngularJS-Documentation/d0c715ef89

Closes #5261
docs(tutorial/step-07): update path to pages in e2e scenarios

The url paths in the tutorial are not in line with the actual tutorial code

Closes #5264
docs(guide/expression): remove misplaced comma

Closes #5280