Add formula for blink1-tool

Was rejected in the past for not having release tags. They now have releases as tarballs on their github.

Has a homebrew-headonly equivalent formula, blink1 (https://github.com/Homebrew/homebrew-headonly/blob/master/blink1.rb), but I feel the formula is misnamed, as it is only building the blink1-tool executable. Not the other components of the project.
The repository https://github.com/todbot/blink1 also contains a separate mac (cocoa), openwrt, linux qt, processing, etc. which are way out of scope of homebrew. The cocoa one is in cask as `blink1control`. I think the scope of this package is everything in the `commandline` directory.

There is also a shared lib target that can be compiled from the same makefile in that directory, but there is no install. What is recommended method for copying libs and headers?

Once I add those do you think it'd make sense to rename it to `blink1`?