gmoccapy_0_9_9_7_6 - solved bug in units after startup

ver. 0.9.9.7.6
- solved the bug wrong units on start up without the preference file
  I needed to replace gscreen.status with my my own status, because gscreen
  does deliver wrong values!
Merge branch 'master' of ssh://norbert@git.linuxcnc.org/git/linuxcnc.git
gmoccapy_0_9_9_7_6 - getting away from unneeded data

- changed some more gscreen.data stuff to self.stat...,
  because IMHO it is not necessary to use data to store something what is availible
  through stat module
gmoccapy_0_9_9_7_6 - get away from gscreen preference

- replaced the preference file handling from gscreen to an own one, expecting that
  gscreen does not mess my files up, if no preference file will be given in the INI,
  we will use gmoccapy.pref stored in the config folder, so there could be differnt
  configs with different settings