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
docs(guide/bootstrap): fix link to angular.js  script in example

code.angularjs.org/angular.js is 404, updated it

Updated http://code.angularjs.org/angular.js in the example to http://code.angularjs.org/snapshot/angular.js
It works fine now.

Closes #7807
docs(TRIAGING.md): clarification for issues that are not reproducable