This commit makes a few changes to project documentation:

* README: Specify the new URL for my blog, i.e. `blog.jwf.io`
* README: Grammar, usage and mechanics changes
* README: Remove dual-license clause, simplify legal language on reuse
* Makefile: Add attributions, add license notice in comments

Signed-off-by: Justin W. Flory (he/him) <git@jwf.io>