qt: change CT_NOW string to CT_NEW in log message

Closes #3852.

Rebased-By: Wladimir J. van der Laan <laanwj@gmail.com>
Rebased-From: 5f2907a, 88d3df4
Add licenses for tests and test data

- 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