Started work on custom object support

NetWork Tasks can now use objects that do not belong to python builtins, users can define their own classes and register them. After registration, entire workgroup can use them.
Further work on custom object support

- Before this commit, users needed to pass the self parameter explicitly when calling methods, this was now fixed by wrapping the methods in MethodWrapper class that passes the self argument automaticaly
Updated documentation to cover netPrint and NetObject
Merge pull request #23 from nidzo732/improvements

Added custom object support with NetObject