alib: regexp - method to check if epsilon is in language described by regexp

Conflicts:
	alib/src/regexp/Alternation.cpp
	alib/src/regexp/Alternation.h
	alib/src/regexp/Concatenation.cpp
	alib/src/regexp/Concatenation.h
	alib/src/regexp/Iteration.cpp
	alib/src/regexp/Iteration.h
	alib/src/regexp/RegExpElement.h
	alib/src/regexp/RegExpEmpty.cpp
	alib/src/regexp/RegExpEmpty.h
	alib/src/regexp/RegExpEpsilon.cpp
	alib/src/regexp/RegExpEpsilon.h
	alib/src/regexp/RegExpSymbol.cpp
	alib/src/regexp/RegExpSymbol.h