THEMA3 added parameter SPUTTER_YIELD_MODEL
THEMA3 sputtering removed unnecesssary line
THEMA3 moved angle calculation to surface class
THEMA 3 reverted ee0fce3
THEMA 3 corrections sputtering and test_syield
Merge remote-tracking branch 'origin/working'

Conflicts:
	IO/parameters.py
	physics/sputtering.py
	physics/test/test_syield.py