SetCoords works for AbsoluteScreenLocateable (sliders, buttons etc)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29447 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3691 refactoring part I to boolean models and panels, both desktop and web

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29449 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Saving for Google Drive works. Todo: not enable saving if opened file cannot be saved as "save as" (like readonly, etc...).

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@29450 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e