Fixed Edit causing other components to flash when selected and when the
window had an alpha set other than 1. Cursor now placed correctly.
Textlength added. translatef removed from edits cursor so it won't affect
children window anymore.

Buttons's Text now centered correctly.
EditBox's text reacts like windows, need to work out a way of detecting
the left and right arrow kays in the TEdit.update procedure so CurPos
can be modifyed there, also need to detect where curpos should be
depending on where the user clicked in the edit