Ticket #3964: adding support for \vspace{}, but with its argument ignored yet

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31572 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3882 shift click works well, up - down!.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31573 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e