Add "monitorCtrlC" utility function

This function will prevent sending of `SIGINT` signal when `Ctrl+C` is pressed. Instead, the specified (or default) callback will be invoked.

Preventing `SIGINT` in projects that are using `gulp.watch` on _Windows_ will suppress the annoying `Terminate batch job (Y/N)?` prompt after `Ctrl+C`. This gives your gulp watcher consistent behavior across all platforms.