This returns the GPG signature for a commit and its contents without the
signature block, allowing for the verification of the commit's
signature.

ssh_stream_read(): fix possible *bytes_read < 0 branch

index: get rid of the locking

We don't support using an index object from multiple threads at the same
time, so the locking doesn't have any effect when following the
rules. If not following the rules, things are going to break down
anyway.

Include dotfiles when copying template directory, which will handle
both a template directory itself that begins with a dotfile, and
any dotfiles inside the directory.

Fix a couple function signatures

Fix the possibility of returning successfully from ssh_stream_read()
with *bytes_read < 0. This would occur if stdout channel read resulted
in 0, and stderr channel read failed afterwards.

Note that we're not checking whether the resize succeeds; in OOM cases,
we let it run with a "small" vector and hash table and see if by chance
we can grow it dynamically as we insert the new entries. Nothing to
lose really.