Code review comment for lp:~rye/ubuntuone-client/add-marshallers

> What is this branch meant to do?

Originally, some method arguments for syncdaemon calls were pretty simple. After some changes were introduced to syncdaemon code, these arguments became no longer valid.
They were replaced by more complex structures. It turned out, that glib does not have marshallers for such kind of object, therefore causing those signals to be trappable by nautilus plugin.

This branch adds missing marshallers signatures, adds target for Makefile to generate corresponding source and header files and adds code to ubuntuone-nautilus plugin to register these marshallers for those complex structures.

Additionally, this branch fixes the ShareCreateError-related bug #496713 as the only thing that was required was to have the correct marshaller registered for ShareCreateError signal callback.