"Delete" menuitem for CAS's context menu. (#3531)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28459 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
make sure sum(list of angles) can go over 360°

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28460 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
4.9.201.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28461 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Ticket #3485: some further improvements could be made in WebSimple by returning null instead of an object containing null

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28462 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Using Java 1.6 now - I sincerely hope SVN does not accept the configuration files, though.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28463 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e