Updated win32 portable build script.

prepare_portable.py:
 Added new site-packages tornado and qrcode.
 Fix incorrect exclude patterns. (by Andy)
 Do not exclude unittest from bundled modules for portable (by Andy)
Updated license files for win32.
requirements.txt: Updated all required packages and current version numbers.
MANIFEST.in: updated file structure
Merge pull request #587 from emanuelschuetze/portable

Updated win32 portable build script.