added doxygen comments added additional option for algebraic simplifications
added doxygen comments
added additional option for algebraic simplifications

[r6096]

jonashaag/libfirm,davidgiven/libfirm,killbug2004/libfirm,davidgiven/libfirm,MatzeB/libfirm,jonashaag/libfirm,8l/libfirm,davidgiven/libfirm,davidgiven/libfirm,8l/libfirm,jonashaag/libfirm,8l/libfirm,libfirm/libfirm,killbug2004/libfirm,davidgiven/libfirm,MatzeB/libfirm,killbug2004/libfirm,davidgiven/libfirm,8l/libfirm,jonashaag/libfirm,davidgiven/libfirm,jonashaag/libfirm,MatzeB/libfirm,MatzeB/libfirm,8l/libfirm,libfirm/libfirm,killbug2004/libfirm,killbug2004/libfirm,MatzeB/libfirm,killbug2004/libfirm,libfirm/libfirm,jonashaag/libfirm,libfirm/libfirm,killbug2004/libfirm,8l/libfirm,MatzeB/libfirm,MatzeB/libfirm,8l/libfirm,libfirm/libfirm,jonashaag/libfirm