import the Font Stash library from https://github.com/memononen/fontstash
incorporate fontstash into the build
add a note about fontstash in the readme Intellectual Property section
render rounded rects with geometry and text with fontstash
request multisampling, and don't request a depth buffer
remove the premade (SVG) tile set image, which is no longer used
remove stb_image, which is no longer used
remove out of date references to tiles.svg from the readme
import the TinyThread++ library from http://tinythreadpp.bitsnbites.eu/
split up global state from static const data
add a thread::start() method to TinyThread++ tthread::thread class
XXX stash