[C++-sig] From python converter for builtin types

[Holger Brandsmeier]

Dear list,

where does boost python define the from python converters for buildin
types such as double / PyLong_Type?

With the help of Changsheng Jiang I was able to modify
builtin_converters.hpp and was able to change a to python converter
for long double to produce numpy.float128. I do not find the place
where the from python conversion is done, though.

-Holger