0.15.1869

• As part of ongoing work for issue #2, repository loading now uses objective-git to read directly from disk instead of parsing command-line output.
  
  This has resulted in substantial performance and reliability improvements for larger repositories, as well as a new, better sorting of the commit tree.
• Tweaked several icon graphics for better contrast, along with some style updates to the commit tree.
• Improved the "Find" and "Find next" keyboard shortcuts in the history view.
• Merge pull request #243 (muhqu) - Add changed-word highlighting to diffs.
• Merge pull request #281 (codiophile) - Add Xcode git path (/usr/bin/git) to the search paths.
• Fixed a crash when a pre-commit hook failed and the "Force Commit" button was pressed.