minor tweaks to build scsynth
Use a more meaningful CPP flag for fpclassify

Old versions of Visual C++ didn't provide fpclassify, but
newer (VC2013) do. Instead of using a MSVC flag, this is changed
to SC_PROVIDE_FPCLASSIFY to be more specific.
Reset fix for stdbool

Use of bool is now supported on MS VC compilers (v. 2013).
Retain whitespace in docstring
Merge pull request #1035 from maedoc/win64build

Small tweaks required for building libscsynth for Win 64-bit