Test case for memory leak in BooleanScorer2
BooleanScorer with flag for taking ownership of subscorers
BooleanScorer2 not giving away ownership of optional and prohibited scorers
Fixing memory leak by deleting temporary BooleanScorer
Merge remote-tracking branch 'origin/bs2_memoryleak_fix'

Conflicts:
	src/core/CLucene/search/BooleanScorer2.cpp
	src/test/search/TestBoolean.cpp
DirectoryIndexReader memleak fix provided by Anthony