extract method

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37166 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
GWT's PopupPanel with slight modification for canceling mouse events. Note that inheritance can not solve our problem.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37167 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
GPopupMenu uses the modified PopupPanel for proper handling of touch and mouse events.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37168 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Added two constructors for Tablet -> Phone -> Web3D chain compatibility.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37169 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Comments added.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37170 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Extract shouldCancelDrag method.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37171 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Reset selectionStartPoint after zooming with right click (needed for tablet long touch zoom)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37172 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Prevent small selection rectangles (helpful on tablets).

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37173 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e