Revert "modify _hashlib and _ssl to *not* automatically build openssl, since we build it by hand"

This reverts commit b06fcf81be50dd76aeee5e6a39d61ec8957a8b7a.
build32-debug.bat: check for presence of nasm.exe
build32-debug.bat: remove accidentally-copied comment
build_ssl.bat: change the directory to the directory containing the BAT file
This also precludes the need to run a "cd" command in the PreBuildStep when run from Visual Studio
build_ssl.py: many improvements and fixes, that ultimately allow it to build openssl-1.0.1e
.gitignore: add /Python-2.7.5/Lib/site-packages/
.gitignore: add buildinf_x86.h and opensslconf_x86.h from openssl-1.0.1e; they are generated by build_ssl.py