Combine MetropolisHastingsSG{1,2}.h
Remove trailing whitespace
Separate implementation of MetropolisHastingsSG1
mv MetropolisHastingsSG1.h MetropolisHastingsSG.h
Merge remote-tracking branch 'origin/sep_impl_mhsg' into dev

Conflicts:
	src/stats/inc/MetropolisHastingsSG1.h
	src/stats/inc/MetropolisHastingsSG2.h