Change the output names. Do away with the Release and Debug

subdirectories.

All final products go into the current directory (i.e., PCbuild).

Object files go into temp-release and temp-debug.

Debug versions of DLLs have _d appended to their basename, e.g. the
debug version of python15.dll is python15_d.dll, the debug version of
python.exe is python_d.exe, and the debug version of parser.pyd is
parser_d.pyd.  (See corresponding patch to importdl.c.)  Uniformly
changed all extension modules to use .pyd, not .dll.