This changes the interface for the C code to return a struct on the
stack that is defined in the code rather than one which is defined by
the cgo compiler. This is more future proof and inline with the
gomobile interface.
This also adds a gomobile interface RcloneMobileRPC which uses generic
go types conforming to the gobind restrictions.
It also fixes up initialisation errors.
- rename C exports to be namespaced with Rclone prefix
- fix error handling in RcloneRPC
- add more examples
- add more docs
- add README
- simplify ctest Makefile
