#2755 improvement

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27508 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Separate API calls for file opening and edit feature switch

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27509 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Added test cases for the tangent command, added test case for ticket 3525.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@27510 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e