Port QT UI to 0.13 base

[zathras-crypto]

Initial PR for the port of the QT UI to 0.13 base.

Includes a simple interface for interacting with any-pair trading, but only intended to provide a reference for sending trades so I've kept it as close to the protocol as possible (no inverting to form a fake buy side for example).

Not perfect, and I'll keep working at some of the remaining bugs, but should provide a solid base to move forward from :)

[dexX7]

Awesome!

There are two CLI commands undocumented (it's a new 0.13 feature to show a build failure for these):

• -disclaimer
• -omniuiwalletscope

For now I adopted the documentation from configuration.md and added it to init.cpp#L502, so maybe you could add those two there, too.

What's the status of this PR? Ready to merge? I haven't tested it yet. :)

[zathras-crypto]

You should be able to safely merge yep, and you should be able to run and use it pretty well (there are no "gotchas" that I'm aware of - but there are some minor display issues like column sizing on balances tab, missing volume stats on metadex page, and a few other bits still "todo", but I'll submit fixes in the coming days.

Really I just wanted to get my work on it to date committed and PR'd so you could start playing with it too :)