Error if no global: project: section

[marsbard]

if no global: section:

$ grua fill

!!!
An exception of type ValueError occured. Arguments:
('list.remove(x): x not in list',)
(<type 'exceptions.ValueError'>, 'grua', 57)
!!!

with a global: section but no project: child

$ grua fill
Traceback (most recent call last):
  File "/usr/local/bin/grua", line 33, in <module>
    if mem.config['global'].has_key('project'):
AttributeError: 'NoneType' object has no attribute 'has_key'

It should not be necessary to include this section, if not included the default value grua should be used (or maybe not... better to just warn that it is required but missing?)