2D/Belyi_Sphere: display dessins as we go
tests/test_hypermap: now long double is fast enough to always use it
tests/test_hypermap: compute the precision properly
2D/Constellation: Implement GMP complex numbers

Note, this requires patching libstdc++ as per the instructions here:
https://gcc.gnu.org/ml/gcc-patches/2014-02/msg01377.html
(this is so that boost::ublas can work with boost::multiprecision).