Adapted a lot.

Added treeRootField* fields
Added treeRootFieldTemplate to Core\Node object
Added Core\EntryPoint object

Fixed the field filterer in Core\Object::get
Fixed `this.definition.treeInterface` check in ka.Tree
Added `destroy` to ka.Layout
Fixed ka.ObjectTable to new entry points
Removed default `labelTemplate` in ka.ObjectTree and fixed there the label rendering of an object entry
Adapted ka.WindowCombine header layout
Added `this.classProperties.nestedRootEdit` check into ka.WindowList and open the edit entry point when click

Renamed the `admin` object key in `config.php` to `entryPoints` and adapted all code that did refers to it

Added new fields for object window class. (nestedMove, nestedRootField*, and nested entry point stuff)

Added backend_chooser.css back
Added new Option to ka.Parse `firstLevelTabPane`

Removed the requirement for a table prefix in installation. Fixed #95.