rename ca -> miniCA
Adds MIT license
Rename res/README.md -> res/README.txt

This is not really a markdown file :)
Fixes path issue with test, when run from main directory.
Refactors miniCA script to move root CA

intermediate CA's are CA's of their own; miniCA will store both 
the root and all intermediate CA's in one directory ($MINICA).

- root will be in $MINICA/root
- intermediates will be in $MINICA/intermediate-<timestamp>