This adds the feature that we show a "last receive" field on a wallet,
and we also change the date format to have "yesterday" style dates
for recent ones.
For each transaction allow to click on it and show lots of further
details about it.
This also fixes various bugs and adds some basic helper methods in
various places.
The QML is barely functional, getting the right data exposed was the
only goal today.
* split the AccountInfo and Payment classes out into their own files.
* Start a 'color' file to switch between light and dark-theme.
* Start a new main GUI which isn't so hacky and ugly.
* Make this actually a desktop app, with menu and file->quit!