Improvements to remote keymapping

Taken straight from http://forum.xbmc.org/showthread.php?tid=142910

These modifications to the default keymap.xml and Lircmap.xml both simplify the remote mappings which creates for a less confusing experience, as well as provide additional functionality (jumpSMS keys are working out of the box).

It seems to do so without confusing long time users pf the old keymap like myself and zag.