We create a special sidebar item for the item library that contains a
ToolButton.

The ToolButton manages the imports for components.

If an import changes we have to delete the cache for the meta info.

Reviewed-by: Kai Koehne

Done by Milian Wolff

Still some flickering and no marks which parts changed.

The icons are taken from the old designer for now.

Alignment at void*-boundaries for small types.
Read out pointer array directly instead of dereferencing ** for
large types for speed.

Reviewed-by: Alessandro Portale

Each Components starts a new scope for ids. Using a stack to check
this properly.

PC register is 'rip' for 64bit and 'eip' for 32bit.

Task-number: QTCREATORBUG-3361

Was aiming at the current line, not the selected one.

Not functional due to missing public API in the editor manager.