Pre-Release for v2.0

This is the pre-release for v2. Signatures and authentication are now supported within the scheme.
You can now do both OTR-Style Symmetric Authentication and Asymmetric Signatures within encrypted files.

You can also create external .sig files. There is also finally an argument-based CLI.

This is a pre-release as more documentation needs to be created before I create an official release. I also might be tweaking some of the commands.