Revert "implementation of y + x = x + y transformation"

This reverts commit 832a57e7.

Conflicts:
	aconversions/src/re2fa/Brzozowski.cpp
	libaregexptree/src/RegExpOptimize.cpp

Conflicts:
	aconversions/src/re2fa/Brzozowski.cpp
	aderivation/src/aderivation.cpp
	aintegral/src/aintegral.cpp
	libaderivation/src/RegExpDerivation.cpp
	libaderivation/src/RegExpDerivation.h
	libaderivation/src/RegExpIntegral.cpp
	libaderivation/src/RegExpIntegral.h
	libaregexptree/src/RegExpOptimize.cpp