Reimplemented the merge function; eliminated the dependencies on `grunt.config.data` and `grunt.utils._.merge`, and replaced with calls to `grunt.config.set`.  The merge function now only performs merge for tasks, and does not attempt to merge targets.
Tests - Added unit tests for the merge function.
Release v1.1.0
- Changed merge to only perform merge 2-levels deep, so that only tasks and targets will be merged.
  This eliminates the dependency on Grunt's internal "data" object, and uses the public "config.set" api instead.
  This also enforces the proper usage of this plugin, because targets should all be unique.