core: Use ostree_commit_get_parent in ostree_repo_resolve_rev
ostree-repo-resolve-rev: Add function to accept a partial checksum

This patch adds a function that will parse a partial checksum when
resolving a refspec.  If the inputted refspec matches a truncated
existing checksum, it will return that checksum to be parsed.  If
multiple truncated checksums match the partial refspec, it is not
unique and will return false.  This addition is inspired by the same
functionality in Docker, which allows a user to reference a specific
commit without typing the entire checksum.

partial checksums: Add function to abstract comparison

This modifies the list_objects and list_objects_at functions
to take an additional argument for the string that a commit starts
with.  If this string arg is not null, it will only list commit
objects beginning with that string.  This allows for a new function
ostree_repo_list_commit_objects_starting_with to pass a partial string
and return a list of all matching commits.  This improves on the
previous strategy of listing refs because it will list all commit objects,
even ones in past history.  This update also includes bugfixes on
error handling and string comparison, and changes the output structure
of resolve_partial_checksum. The new strcuture will no longer return FALSE
without error.  Also, the hashtable foreach now uses iter.  Also
includes modified test file
Fix typo in previous commit
core: Unify object deletion code with prune

The prune API duplicated logic to delete objects, and furthermore the
core API to delete an object didn't clean up detached metadata.

Fix the duplication by doing the obvious thing: prune should call
_delete.

https://bugzilla.gnome.org/show_bug.cgi?id=733452
core: Do enumerate content objects in archive-z2 repositories

Prune has worked fine on bare repositories for some time, but now that
I finally try to delete data on the server side, I notice we weren't
actually enumerating content objects =/

That caused them to not be pruned.

https://bugzilla.gnome.org/show_bug.cgi?id=733458
core: Do enumerate ff/ objects as well

An embarassing off-by-one here.  I noticed we weren't pruning them.

https://bugzilla.gnome.org/show_bug.cgi?id=733458
repofile: Avoid segfault if querying child in non-directory

The user might "ostree ls /usr/bin/bash/blah", which previously would
segfault.

A somewhat related future enhancement here would be for "ostree ls" to
follow symbolic links.

Reported-by: Dusty Mabe <dustymabe@gmail.com>

https://bugzilla.gnome.org/show_bug.cgi?id=733476
Merge branch 'master' of http://git.gnome.org/browse/ostree

* 'master' of http://git.gnome.org/browse/ostree: (7 commits)
  repofile: Avoid segfault if querying child in non-directory
  ...
Add start-time to OtPullData and use it for B/s on progress output.