Minor cleanup (#214)

Minor cleanup (#214)

- use `grep -E` and `grep -F` (`egrep` and `fgrep` are non-standard)
- use same hashbang style for all test scripts
- use explicit comparisons in test scripts
- remove redundant ; from test scripts
- make test script not executable, just like all the other scripts
- unify codestyle across all test scripts
- make openssl license exception clearer by having it at the top
- use modern links in COPYING. The text now matches:
  https://www.gnu.org/licenses/gpl-3.0.txt
- fix typo