[Ohrrpgce] SVN: teeemcee/11493 thingbrowser: add 2nd "Add new thing" button to the end of the list

[subversion at HamsterRepublic.com]

teeemcee
2019-12-24 20:04:34 -0800 (Tue, 24 Dec 2019)
341
thingbrowser: add 2nd "Add new thing" button to the end of the list

This makes the thingbrowsers behave more like all the other browsers, so you
can hit End-Enter to create a new thing.

Also I made the "Add new spriteset" button stretch across the screen, looks
better and fixes the ridiculous case of it not being below the last spriteset
---
U   wip/data/spriteset_browser.slice
U   wip/data/thingbrowser.slice
U   wip/thingbrowser.bas