[Core] Improve plugins support

[agomezmoron]

Nowadays some plugins are supported to be added/removed. That list should be analyzed and improved to add the most used in the phonegap cloud.

[agomezmoron]

Think about the possibility to extends its usage like: if an user wants to add/remove a plugin that doesn't exist in the list, how are we going to manage it? Do we want to support it?

[natete]

Maybe it'd be nice to add whitelist by default so the user can use livereload out of the box.