IDE: Disable the checkbox for BuildModes on top of Project options instead of hiding it.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45639 4005530d-fff6-0310-9dd1-cebe43e6787f
IDE: Update the GUI for BuildModes after importing them. Disable import/export with invalid filename.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45640 4005530d-fff6-0310-9dd1-cebe43e6787f