feat(filter): Add comparison function to filter

Add optional comparator function argument to $filter('filter')(array,
expression, comparator) such that the comparator function is used to
compare the values and predicates.  When true, defaults to equality.
When missing defaults to substring matching.
chore(reakefile): auto install npm packages
fix(compiler): Allow startingTag method to handle text / comment nodes
fix(resource): Update RegExp to allow urlParams with out leading slash

Will allow reoucese to be loaded from a relative path
Example:
var R = $resource(':path');
R.get({ path : 'data.json' });

Example usage:
Load resources in applications not using webserver, ie local webapp in 
on a tablet.
feat(noConflict): restore previous angular namespace reference
fix($rootScope): minor typo fixes
docs($parse): document function argument types, fix minor typo
feat($parse): added `constant` and `literal` properties

* `literal` is set to true if the expression's top-level is a JavaScript
  literal (number, string, boolean, null/undefined, array, object), even
  if it contains non-literals inside.

* `constant` is set to true if the expression is known to be made
  entirely of constant values, i.e., evaluating it will always yield the
  same result.

A consequence is that a JSON expression is guaranteed to be both literal
and constant.
feat(scope): only evaluate constant $watch expressions once