improve french translation.

Cleaned up commit from l4nce0

    Now when the program starts the last temp is set for Heater and Bed. Also a (user) is attached if it is a manual entry.

last used serial port pre-selection logic change, based on if it is autodetected to be present or not

Closes #41
Closes #51

Paint travel moves with a different colour

French translation fix

Fix inverted Y coordinates in normals

Only adds the STL filename to the listbox, not the whole path.

Conflicts:
	plater.py