Allow relative aliases

Because the current configuration was very restrictive, i.e.: forcing you to
place a Yii::import() call in the configuration file, instead if being
able to use 'import' or 'components' with fully specified class path, i've
made some modifications to allow this.
Merge branch 'relative_aliases'
conform to indetations with spaces (ugh)
Fix wrong assumption that Yii::import takes relative args.

My mistake... sorry. ;)
Merge branch 'relative_aliases'