This change is motivated to make it easier to run the unit tests:

defined two executable targets in the cabal file
added run_unit_tests.sh script
one test is failing independent of the changes:

```
Failure in: 0:interaction:2:tab completion:0
tests/RunTTY.hs:106
expected: ["dummy-\206\188\206\177\207\131/\r\nbar \207\130\206\181\207\129\207\132\r\n0:dummy-\206\188\206\177\207\131/"]
but got: ["dummy-\206\188\a\a"]
```