Terminal used to run `yes` at around 400 lines per second
This patch pumps that to over 100'000 lines per second!
There are 2 optimizations done:
1. only invalidate window once after rendering is done
2. if printing more than `rows()` newlines skip prior data
userspace programs are now in userspace/programs
userspace tests are now in userspace/tests
This makes listing userspace projects much cleaner. Libraries were
already separated to their own directory, so other programs should also.
Bananymous