Added test for the issue that SEED identifiers are not passed to
evalresp.

Also introduced the mock library.
Added mock library to setup.py.
Passing the SEED identifiers to evalresp.
Added test that evalresp actually uses the SEED identifiers to extract
different responses.
Adjusting some tests to the changes.
Changelog
fix test (relied on some automagic in trace.simulate() included in master, automatically putting missing date in seedresp)
install mock in travis
Merge pull request #687 from megies/evalresp_fix_rebase_releases

Evalresp fix (see #686) rebased onto releases