Add missing BNFC.Backend.Base to cabal file
Add a separate test suite for system tests

First, some backend (cnf) require bnfc to be installed and not just
build, which doesn't work with `cabal test`.
Second, this way, the system tests are not included in the distributed
bnfc package and don't clutter the cabal file.
Make system test suite fail if at least one test fails
Update gitignore for cabal sandboxes
Use HTF in the system tests and fix the java tests
Remove system tests from source/
Cleanup shelly dependency in unit tests
Remove regression tests from source/
Move test/src/ to simply test/
Rename system-tests to testing

and remove the old content under testing/
Fix Haskell/CNF test suite

The generated test program uses a different name.
Remove a redundant `do`
Add a jar with JLex and java cup for testing
Merge pull request #104 from gdetrez/test-improvements

Test improvements