make the c++-2011 feature set of GCC 4.4 mandatory

we now produce an error even if the module in question does not
actually use some of these features.
replace boost::array by std::array

GCC 4.4 supports std::array, so there is not much point in keeping
compatibility with ancient compilers...
Merge pull request #289 from andlaus/make-gcc44-mandatory

Make gcc44 mandatory