Update preferences

Some things I ran across when going through the preferences menu and trying to get rid of the TODO:s there:

• Remove Cursor rendering option
• Add Pointer handedness description
• Add Swap compression - Description created from part of Ell's commit messages for GEGL and GIMP.
• Fix a place where number of options had changed.
• Other small fixes for consistency (behaviour->behavior, no space in i.e, self-explanatory with hyphen everywhere)

v2: On second thought, replace quote with guilabel for the menu additions.