- Add license headers to source files (years based on commit dates)
in `src/test` as well as `qa`
- Add `README.md` to `src/test/data` specifying MIT license
Fixes#3848
* Use the latest version, with limited memory usage, and path to
on-disk db (try mouting qa/tmp on a tmpfs)\
* enable -debug=net
* re-enable BitcoindComparisonTool in pull-tester