Number in task title is now captured in regex

The number was given by the lecturer and is used to differentiate between different versions of the tasks, thus it should not be omitted.

Closes #1

lib/xls.py

@@ -44,7 +44,7 @@ class XLSConverter(lib.generic.Converter):
 user_t = namedtuple('user_head', 'name matrikel_no')
 
 # one task has a title and id and hpfly code
-task_head_re = re.compile(r'^Quellcode Frage (?P<title>.*?) ?(\d{8})?$')
+task_head_re = re.compile(r'^Quellcode Frage (?P<title>.*?)$')
 
 # nor parsing the weird mat no
 matno_re = re.compile(r'^(?P<matrikel_no>\d+)-(\d+)-(\d+)$')