Adding pst support and attachment support for rfc822

I added the libpst library and a pst module for application/octetstream. Binaries only included for x64 linux. It exports a pst to a directory structure with .eml files. Next to that, the .eml parser is improved to export attachments and index those.

One special modification: modules get the file object instead of only the fullpath.

Tested on the Uforia machine against all test data.