* sdk: Add split/unslit editor events (thanks arthurzmj)

git-svn-id: https://svn.code.sf.net/p/codeblocks/code/trunk@9835 2a5c6006-c6dd-42ca-98ab-0921f2732cef
* keybinder: Make the plugin use the new events (thanks arthurzmj)

git-svn-id: https://svn.code.sf.net/p/codeblocks/code/trunk@9836 2a5c6006-c6dd-42ca-98ab-0921f2732cef
* issue a warning (info window) if the user tries to access a member of a global variable that has not been defined (GCV is defined, user-defined member not)
* issue a warning (to debug log) if include folders evaluate to empty values due to invalid macro usage, for example

git-svn-id: https://svn.code.sf.net/p/codeblocks/code/trunk@9837 2a5c6006-c6dd-42ca-98ab-0921f2732cef