[ALOY-1326] Paths and names of Collections/Images/Controllers is not consistent.

The name of the controller can also be a relative path. But to make it uniform (just like with images) you should be able to add a / in front of the name/path. It currently doesn't support that. This fix resolves that for controllers,models and collections, and adds to the documentation it can also be a relative path. An example why this should be supported is because it is consistent for everything. Image names/paths with a leading / on Android is even required, and a controller name/path with a leading / is generating errors. This leads to unexpected issues, and confusion. This fix makes it consistent:

Alloy.createController('name'); // will work
Alloy.createController('/path/to/controller'); // will also work
$.imageView.image = '/path/to/image.png' // will (only) work
Alloy.createCollection('name'); // will work
Alloy.createCollection('/path/to/collection'); // will work

Consistent behaviour across all names/paths leads to expected functionality. Exceptions make it confusion. This fixes that