31/10/2019: ninja replaced by samurai

The build tool ninja has been replaced with samurai.

This replacement is 1:1 compatible with ninja, absolutely tiny in size, doesn't require python to build and is simply simpler.

The one downside is that a smidgen of manual intervention is required. Simply remove ninja (KISS_FORCE=1 kiss r ninja) and run kiss update.

The sources for Samurai can be found here: https://github.com/michaelforney/samurai