added --enable-optimization, thrown -g -O specifics out of Makefile.am's
--enable-optimization is added to each configure.ac and is linked with --enable-debug (no debug and optimization at the same time, debug is normally off and -O2 on), implemented via C(XX)FLAGS
Henceforth, -g, -O and -cc=... specifics are thrown out of the Makefile.am's, so that the optimiziation and debugging is streamlined throughout the whole package