LCL: Add drag/drop functionality to TArrow. Issue #26756, patch from Mike Thompson.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46278 4005530d-fff6-0310-9dd1-cebe43e6787f
Add Mike Thompson to contributors list.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46279 4005530d-fff6-0310-9dd1-cebe43e6787f
Designer, Menu Editor: Implement drag'n'drop for moving items. Issue #8733, patch from Mike Thompson.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46280 4005530d-fff6-0310-9dd1-cebe43e6787f