Tweak dev and default grunt tasks

Preen is only needed when installing new components so take that out of
the default task.

Dev task was set up to run sass after watch which can't happen since
watch loops forever, watching. Instead, do a rebuild of js and sass
files before starting the watch.

// FREEBIE

Gruntfile.js

@@ -194,8 +194,8 @@ module.exports = function(grunt) {
     }
   });
 
-  grunt.registerTask('dev', ['connect', 'watch', 'sass']);
+  grunt.registerTask('dev', ['default', 'connect', 'watch']);
   grunt.registerTask('test', ['jshint', 'jscs', 'connect', 'saucelabs-mocha']);
-  grunt.registerTask('default', ['preen', 'concat', 'sass', 'copy']);
+  grunt.registerTask('default', ['concat', 'sass', 'copy']);
 
 };