fix($http): allow interceptors to completely override headers

Closes #2770
chore(package.json): fix name to work with latest NPM
fix(angular.equals): add support for regular expressions

Regular expression objects didn't used to be considered to be equal when using
'angular.equals'. Dirty checking therefore failed to recognize a
property modification.

Closes #2685
fix(grunt): cache version number

caching the version number speeds up the build and preserves resources.

this also fixed EMFILE error that now occurs on some macs.
style(ngMock): add missing whitespace
docs(di): promote registering controllers on modules
feat(ngPluralize): add alternative mapping using attributes

Add an alternative way to define a mapping for ng:pluralize using
attributes instead of the `when` attribute

Closes #2454
test($q): improve logging of callback invocations
feat($q): added support to promise notification

It is now possible to notify a promise through deferred.notify() method.
Notifications are useful to provide a way to send progress information
to promise holders.