Code now only restarts watchers for the asset groups in the changed asset manifest file, rather than *all* asset groups. The "build" task now forces rebuild of a given asset group if its asset manifest file is newer than its concatenated output. Refactored and cleaned up the code.
Removed variable option for rebuildAlways
Set watch task to always check `watchPaths` and populated that based on `watch` variable option (if the option is present, it will watch files designated in `watch` as well as files designated in `input`. Otherwise, it will only watch files designated in `input`.
Including some help text / comments
Set rebuildAlways to default to true when not specified
Set generateSourceMaps to default to true when not specified
Including files specified in 'inputs' into the watch list.
Added optional properties to the Assets.json to support separating watch and build lists.
Also added support for excluding sourcemaps as well as forcing rebuild.
Requires gulp-notify (added fancier notification for process completion).
