Don't restrict the adapters.

Also show the standard ones, not only the most suitable ones. Sometimes
you might want to just edit the raw data.
Added a CEGUI helper class.

This contains functions for helping out with handling CEGUI in Lua.
Typically this is for methods which aren't exposed in Lua through the
standard bindings.
Fixed issue with windows not showing.

There's an issue with the bottom window in a LayoutContainer not showing
when new windows are added. This fixes that issue, but the solution is
kinda hackish.