Redo py3k branching from trunk again

[SVN r52115]
preliminary work - 14 BPL .cpp files can be compiled with Python 3 now.

[SVN r52118]
More BPL .cpps compiled. A part of Python 3 module initilization support done.

[SVN r52131]
Fix a typo which cause many tests crash.

[SVN r52133]
Fix more bugs due to typo.

[SVN r52134]
get builtin_converters.cpp compiled under Python 3

[SVN r53278]
more fixes to get testcases work, includes module init and other minor fixes

[SVN r53285]
more minor fixes to get test cases passed

[SVN r53315]
fix for next() -> __next__() name change in py3k

[SVN r53322]
implemented a arg_from_python converter that converts py3k unicode to const char*, not an ideal solution, just experimenting.

[SVN r53653]
implemented unicode -> const char* lvalue converter for py3k, by using _PyUnicode_AsString() C-API

[SVN r53692]
clean other attempts for making unicode -> const char* conversion work, since now we have the right way in previous commit.

[SVN r53693]
change encoding annotation iso-latin-1 to latin-1

[SVN r53698]
fix __nonzero__ -> __bool__ change

[SVN r53718]
change TrueDivide to FloorDivide to make the semantic conform with C/C++ '/' operator

[SVN r53721]
fix the static property initialization caused by Python internal change in property_init()

[SVN r53731]
fix definition of opaque<Pointer>::type_object

[SVN r53754]
fix test dependence of polymorphism2_auto_ptr

[SVN r54643]
several fix for the exec test case to make it runs under py3k

[SVN r54644]
fix the 'try' test case

[SVN r54645]