Feedback and Unit Tests

* Feedback: table columns shown on "submissions" page depend on feedback
* Unit Tests:
    * changed semantics
    * implemented server-sided unit tests
    * seperate unit tests from normal submissions
    * special "details" page
I agree this should be presented in a way different from a failure in the testcases. But currently, compiler errors actually make the command line tool (cmsGerMake) crash:
```
Traceback (most recent call last):
  File "/usr/bin/cmsGerMake", line 9, in <module>
    load_entry_point('cms==1.2.0rc0', 'console_scripts', 'cmsGerMake')()
  File "/usr/lib/python2.7/site-packages/cms-1.2.0rc0-py2.7.egg/cmscontrib/gerpythonformat/GerMake.py", line 101, in main
    args.clean).make()
  File "/usr/lib/python2.7/site-packages/cms-1.2.0rc0-py2.7.egg/cmscontrib/gerpythonformat/GerMake.py", line 67, in make
    local_test=self.local_test)
  File "/usr/lib/python2.7/site-packages/cms-1.2.0rc0-py2.7.egg/cmscontrib/gerpythonformat/ContestConfig.py", line 469, in _maketask
    tdb = task._makedbobject(file_cacher, local_test)
  File "/usr/lib/python2.7/site-packages/cms-1.2.0rc0-py2.7.egg/cmscontrib/gerpythonformat/TaskConfig.py", line 1222, in _makedbobject
    self._do_test_submission(sdb, ddb)
  File "/usr/lib/python2.7/site-packages/cms-1.2.0rc0-py2.7.egg/cmscontrib/gerpythonformat/TaskConfig.py", line 1501, in _do_test_submission
    verd = details["verdict"]
KeyError: 'verdict'
```
How about another verdict (something like ``(2, "Compilation failed")``)?