vdsl v1.2.0:
* Added README page in Markdown format, complying with
Workshop style.
* Enhanced script docs.
* Added dependency checks and warnings.
* Branched local copies of bash script libraries from
the to remove dependence on that package for
local testing, so at least '-h' and '-man' can be
run without errors.
* No functionality changes other than new behaviors
for failed dependency checks.