This updates the installer to install Python 3.8 instead of 2.7. This

was chosen instead of the newly-released Python 3.9 due to its

stability, though we may move to 3.9 in a future release.
The installer also now installs a 64-bit build of Python (and of our

wrappers) instead of 32-bit. This should be fine for most users. Some

work was done to aid in creating a 32-bit installer later, if we get

user feedback requesting one.
There's also some improvements to the Wix installer files. Strings are

localized, comments were added, and some sections are cleaned up.

Built the installer and tested it on Windows. Successfully installed

RBTools, and verified that I could run it from a new DOS shell.
Verified the files were placed in C:\Program Files and not

C:\Program Files (x86).