IDE: Copy also ProjectBuildMode.InSession in Assign

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40857 4005530d-fff6-0310-9dd1-cebe43e6787f
IDE: Buildmode window refactoring.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40858 4005530d-fff6-0310-9dd1-cebe43e6787f