The Toolbar is the new thing from Google which acts as an ActionBar.
It is not a special view like the action bar is, it is
implemented and added to your layout the same as any view.
The InnerView classes of the swap workflow have the choice of what
colour to make the toolbar, so that they can distinguish themselves
as per the mockups (some deep blue, others bright blue).
Added icons for close, but they don't do anything yet.
Minor tweaks to layout so that it looks more like the latest mockups.
Fixes#240.
To make this easier, I added a script to aid in downloading icons.
Checkout F-Droid/tools/download-material-icon.sh for more details.
The icons are licensed under the CCv4 attribution license, which I
added a shout out to under "License" in the README.md.
