libtorc-core: Make service invocation reentrant.
libtorc-core: Convert JSON serializer to QJson
libtorc-core: Make PList serialiser consistent with JSON output
libtorc-core: Use compact JSON format
libtorc-core: Extend use of Q_CLASSINFO to specify return type for Maps

- this allows more user user friendly XML, JSON and PLIST returns that
specifify the a given type for the underlying list.
- allows external clients to apply a simple top level check to returned
data.

So we might have:

<discs>
   <disc1>
       ....
   </disc1>
   <disc2>
       ....
   </disc2>
</discs>

instead of:
<disc1>
    ....
</disc1>
<disc2>
    ...
</disc2>
libtorc-core: Make JSON serialiser consistent with other serialisers

- by adding a top level object for Maps
libtorc-core: Simplify PList serialiser

- by reverting previous commit:) (which is no longer required)
libtorc-core: Improve XML serialiser output

- removes redundant VariantMap tags and greatly simplifies output
libtorc-core: Use compact JSON
libtorc-core: Invert name and method in GetServiceList

- trying to add a path to xml tags isn't going to work...