This halves the amount of code we have to take into account for dealing
with the config.
There is a slight change in the API. Config.get_multivar() returns an
iterator instead of a list, which lets us reuse code from the general
iterator and is closer to libgit2's API.
Casting a pointer to a non-pointer type is something which you should
never do. Instead, do something a bit more convoluted, but which is
guaranteed to give us the right pointer, as well as making sure that the
memory we exchange between python/cffi and the C extension is of the
right pointer size.
While we're touching this code, fix which object we pass to the Remote
constructor to keep alive. We need to pass the Repository object to
stop it from becoming unreferenced (and thus freeing memory the remote
needs) instead of the git_repository pointer.
This moves enough code into python with CFFI to pass the test_remotes
unit tests. There is no credentials support yet.
There is a small change in the return value of Remote.fetch() in that we
now return a TransferProgress object instead of extracting a few values
into a dictionary.
Now we figure out whether it is a direct or symbolic reference based on
the type and value of the target. This guessing will fail in very very
rare situations, for that we still have the explicit lower level API.
