Implemented git_tree_entry_bypath within Tree.__getitem__
config test: the loop should return 0

Returning anything else makes the loop stop, which stops us from
getting to 'core.bare' which the test is looking for.
travis: do a shallow clone of libgit2 and don't build the tests

This just adds time to the tests. We're not testing the library, but
the bindings, so do a shallow clone and stop cmake from building clar.
Merge remote-tracking branch 'carlos/less-work'
Added error checking when calling git_tree_entry_bypath
Run the diff tests
diff: expose the hunk header

We can rebuild it from the data we already have, but this will allow
us to get the function headers in it once the library supports it.
diff: make sure malloc succeeds
diff: add old and new OID values to Hunk

These can be important, and are necessary to create a patch from this
data.
diff: expose the filemode through Hunk
git_index_read_tree now accepts a stats structure

Indexer stats may be NULL but the method still needs three arguments
Added Repository.create_blob_fromfile
Added unit test for Repository.create_blob_fromfile
docs: Fix 'Diff' example

t1 should point to a tree, not a commit.
Merge remote-tracking branch 'edavis/fix-diff-example'
More obvious diff example

By diffing HEAD~1 with HEAD, we show the effect of the latest commit.

The provided example diffed HEAD with HEAD~1, which shows a diff
that goes back in time.
Make time and offset arguments to Signature optional

If these are left blank, use git_signature_now to insert the current time.
Specifying one but not the other causes a TypeError.
Test inlcluded.
Merge remote-tracking branch 'encukou/git_signature_now'
Add GIT_FILEMODE_* constants

These are useful when putting files in the treebuilder
error: replace `GIT_REVWALKOVER` with `GIT_ITEROVER`.

This catches up with changes in libgit2:

  commit f335ecd6e126aa9dea28786522c0e6ce71596e91
  Author: Russell Belfer <rb@github.com>
  Date:   Thu Aug 30 14:24:16 2012 -0700