global: kwalitee fixes in invenio.testsuite

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
base: eval is evil

* Using ast.literal_value instead of eval to parse user provided values.
  Safer and more reliable (bool("False") -> True)

* Removing the checks that the new type corresponds with the known type
  for the value.

* Adding some tests and invenio.base to the base set of packages.

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
global: test cases with no TEST_SUITE

* Adding an automagic creation of the TEST_SUITE by inspecting the
  content of the loaded module. Any TEST_SUITE defined will be used if
  present.

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>