Stack Wallet v2.1.0 BETA

This is the desktop BETA versions for Stack Wallet upcoming release 2.1.0.

This version has Monero and Wownero working on all desktop platforms (Windows, Linux, and Mac).

Previously only Monero worked on Linux and Mac (not Wownero), and neither worked on Windows.

This was accomplished using a new Monero Dart library from @mrcyjanex. Any beta testers would be very appreciated.