allow invalid property bindings in disabled items

Task-number: QBS-409

Change-Id: I62093d078f9a733c86208b7ad2c8685cb5986b14
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
move the setup of the base module to its own function

Also, do the setup only once and not for cache hits.

Change-Id: I784d5127a3a7a89f605b18c697ce8a53f11171b9
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
call Module.validate after the base module setup

Special base module properties like hostOS were not available in
Module.validate.

Change-Id: I14f506dea2eb10edc726dd5a789e04e97f06f9a5
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>