fix windows test run
unit test round 2
attempting to fix ccache use on darwin
made ccache optional, no longer pulls clang on darwin build
fixing darwin build from Dockerfile
fixed missing nproc on OSX
updated readme to include regtest example, build examples
fix QT unit tests
made -j get passed down, added build.sh
This contains significant rebase / merge / testing work by Naut
<lbrynaut@protonmail.com>, Anthony Fieroni <bvbfan@abv.bg> and Brannon
King <countprimes@gmail.com>.
Some patch implementations can't handle fuzz / too much divergence from the
original code.
This just tweaks the context code around the patch so that less-sophisticated
patch implementations (such as on Alpine Linux) can apply the patch without
errors.
