#4635 preventing "single branch": if the only leaf is moved, the branch disappears.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37253 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#4701 - add blacklist for specific GPUs

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37254 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#4701 - remove debug and format code

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37255 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e