[connman-qt] Add ResetCountersForType method.

Add a method to reset all counters for the specified type of network
service.
Merge pull request #86 from amccarthy/counters

[connman-qt] Add ResetCountersForType method.
[connman-qt] Bump version to 1.0.41.
[connman-qt] remove asserts as all properties are not always given.
this fixes crashes elsewhere.