runtests.py recompiles needed stuff
Improve command line interface

* Proper overriding for concuerror_options/0 defined in files
* Options work when concuerror:run/1 is used directly from an Erlang shell
* 'Direct' loading (via -f) has been improved
* A few more sanity checks were added
* Got rid of the 'undefined type' warning by Dialyzer!