reduce code overhead for tuple constants by using PyTuple_Pack() instead of step-by-step tuple construction code

fix early module registering by using FQMN instead of plain module name, added test for init-time reloading of modules in packages

--HG--
extra : transplant_source : Y%1C%3A%07%2C%60%B0%F0.%EA%B1%23%3F%0E%20%89%13%C5%C24

--HG--
extra : transplant_source : %F9%FF%8Ai%99OV%BFd%F7%147%19pm%5D%DF%98%D4%FC

in Py3.3, use new PyImport_ImportModuleLevelObject() C-API function instead of equivalent Python call to __import__()

--HG--
extra : rebase_source : 8127709bcb8f2d8f6cfd91a1e46b16dcb7734765

--HG--
extra : rebase_source : d7e8fd6a1d192a73dfac8c38a502dda52be14899