Add Rugged::Patch.from_strings.
Update to latest libgit2.
Merge pull request #323 from libgit2/arthur/diff-buffers

Add `Rugged::Patch.from_strings`.
Mention CMake more prominently

We need CMake in order to build with the functionality most people want,
so let's mention it explicitly.
Fix a typo.
Merge pull request #326 from libgit2/cmn/cmake

Mention CMake more prominently
Fix a typo in the Readme.
Require CMake for all builds
Merge pull request #327 from libgit2/vmg/clean-build

Require CMake for all builds
Mention that we now require CMake to build Rugged.
Allow Rugged to be built using CMake 2.6.

CMake 2.6 does not support the `--build` flag, but instead supports
building through GNU Make just fine. This is also compatible with all
newer CMake versions.
Fix a stray semicolon that could lead to a segfault.

We'd try to rename a reference even if loading it failed.
Merge pull request #328 from libgit2/arthur/bring-back-cmake-2.6-support

Allow Rugged to be built using CMake 2.6.
Test for `gmake` first.
Merge pull request #329 from libgit2/arthur/fix-typo

Fix a stray semicolon that could lead to a segfault.
Wrong doc in rb_git_remote_connect

correct direction in `rb_git_remote_connect`, it should be :push instead of :pull
Merge pull request #330 from bachue/patch-1

Wrong doc in rb_git_remote_connect
Get the Rugged version from `describe` output
Update to latest libgit2.
Update to new options structure names.