1. fixed nits
2. removed astype() call
3. after_main_loop used for output
4. removed unused import of LBGeometry2D
Merge remote-tracking branch 'origin/multicomp' into multicomp

Conflicts:
	examples/multi_fluid/ternary/sc_drop_2d.py

1. fixed nits
2. removed astype() call
3. changed after_step to after_main_loop
4. removed unnecessary LBGeometry2D import