Pushed text editor fixes; now editing code/asm should work properly

[Zoltan Padrah]

Hi,

I've just pushed some fixes to git master for fixing the text editor
(issues with duplicated shortcuts, undo/redo and printing). Now
editing code should work fairly well. If it does not, please let me
know.

Writing a tutorial for simulating code on a pic is still on my todo
list; It will have a section "fixing SDCC on debian/ubuntu for PIC
microcontrollers".

Have fun,

 Zoltan