CollectShell improvements

[rchavik]

Right now, the CollectShell only works for webroot/uploads or any directory one level below webroot.

It also assumes that the original files is in webroot/uploads while resized files in webroot/uploads/resized.

Other plugin, such my rchavik/gallery stores the files in webroot/galleries/<album-slug>/<resized-file>.jpg, while the original file is stored in webroot/galleries/<album-slug/source/.

Either:

• Figure out a way to 'collect' these files and store them appropriately in the assets table
• or Write a shell that automatically collects and rename/move the physical files according to the the Assets' plugin convention

[rchavik]

Note: the shell mentioned will be out of scope of this plugin. but the Assets plugin should provide an API and convention for storing these files