We always calculate multiple merge bases, but up to now we had only
exposed the "best" merge base.

Introduce git_oidarray which analogously to git_strarray lets us return
multiple ids.

When adding new config section, handle config file not ending with LF

Handle local file:/// paths on Windows

Windows can't handle a path like `/c:/foo`; when turning file:///
URIs into local paths, we must strip the leading slash.

ssh: provide a factory function for setting ssh paths

git allows you to set which paths to use for the git server programs
when connecting over ssh; and we want to provide something similar.

We do this by providing a factory function which can be set as the
remote's transport callback which will set the given paths upon
creation.

We used to assume a refspec would only have an asterisk in the middle of
their respective pattern. This has not been a valid assumption for some
time now with git.

Instead of assuming where the asterisk is going to be, change the logic
to treat each pattern as having two halves with a replacement bit in the
middle, where the asterisk is.

Move yield to the tests and enable for FreeBSD