Awesome, will look this through!

They might be better documented under "ILayer"

Conceptually, the Layer class is now in place of ILayer. Earlier you needed to conform to an interface for custom layers, now you're required to inherit from Layer.

Technically aren't both true? You now require to inherit from L.Layer AND implement onAdd and onRemove?

What about splitting up "Utilities" and "Interfaces" into "Utilities" and "Base Classes"? Since for every interface you are now required to extend from a base class and implement specific methods, onAdd, onRemove, addHooks, removeHooks, ect...

Utilities

• Browser
• Util
• Transformation
• LineUtil
• PolyUtil

Base Classes

• Class
• Evented
• Layer (Replaces ILayer)
• Control (Replaces IControl)
• Handler (Replaces IHandler)
• Projection (Replaces IProjection)
• CRS (Replaces ICRS)

Technically aren't both true? You now require to inherit from L.Layer AND implement onAdd and onRemove?

Yeah, you're right. Although this time we can get rid of the "interface" concept in docs alltogether, making things simpler to understand, because these interfaces are not sophisticated anymore — we can add a section on custom use of each class like L.Layer without calling it an interface in the table of contents.

I like the "Base Classes" suggestion.

I'll split this up into "Utilities" and "Base Classes" and update this PR.

• Split things up into "Utilities" and "Base Classes" as previously discussed.
• Move all docs for Control under the new "Base Classes" Header
• Gave Layer and Control docs some more love
• Remove references to "interfaces"

This is now a pretty huge PR so it would be great if @mourner, @danzel or someone could look over the changes so I can continue to base future docs on this set of changes.

Rebased and merged to gh-pages-master