chore($ngLocale): Generate ngLocale files from the Closure code.

-   Addresses issue #2152
-   Generates new locale files that include date symbols present in [datetimesymbolsext.js](https://code.google.com/p/closure-library/source/browse/closure/goog/i18n/datetimesymbolsext.js)
-   Compare differences in `src/ngLocale/angular-locale_sr-latn-rs.js` to get a feel for the changes.
-   Uses code from branch [i18n_closure_logic](https://github.com/chirayuk/angular.js/tree/i18n_closure_logic) (a different pull request.)