docs(loader): improve explanation of modules
docs(guide/services): fix link to wikipedia article containing parentheses

Fix in a mis-parsed link with ')' symbol in it

Closess #7775
feat(input): add $touched and $untouched states

Sets the ngModel controller property $touched to True and $untouched to False whenever a 'blur' event is triggered over a control with the ngModel directive.
Also adds the $setTouched and $setUntouched methods to the NgModelController.

References #583
docs(errors/$compile/nonassing): fix reversed attribute and scope property names
docs(guide/services): fix link to services api

Closes #7795
perf($http): move xsrf cookie check to after cache check in $http

$http was previously checking cookies to find an xsrf-token prior to checking
the cache. This caused a performance penalty of about 2ms, which can be very
significant when loading hundreds of template instances on a page.

Fixes #7717