ignore bower_components

Don't track files in `bower_components`, so users can opt to pull in 3rd party libs via bower without crashing the watch process do to too many files

lib/serve/watch.js

@@ -3,7 +3,7 @@ var gutil = require('gulp-util');
 
 module.exports = function(liveReload) {
 
-  gulp.watch(["./**/*", "!./node_modules/**/*"], function(evt){
+  gulp.watch(["./**/*", "!./node_modules/**/*", "!./bower_components/**/*"], function(evt){
 
     gutil.log(gutil.colors.cyan(evt.path), 'changed');