Log Message:
gource: Update to 0.51

0.51:
 * Fixed --font-file relative path handling.
 * Fixed a bug in resolving the repository root directory from a relative path.

0.50:
 * Right mouse button rotation now pivots around the camera.
 * Added --font-file option.
 * Added --enable-font-file option to configure.
 * Added --no-time-travel option (Lars Schmertmann).
 * Added --dir-name-position option (Lars Schmertmann).
 * Added --file-extension-fallback option (Lars Schmertmann).
 * Added --user-show-filter option (Victor Lopez).
 * Added --disable-input option (Joey Parrish).
 * Added --loop-delay-seconds option (Joey Parrish).
 * Added --font-scale option.
 * Added filename, dirname and user font size options (Carl Colena).
 * Added workaround for FFMpeg error parsing Gource PPM video output.
 * Fixed a bug in the Mercurial log parser that caused changes to be missed.
 * Fixed file removal being cancelled by an action with an earlier timestamp.
 * Fixed a bug in the log file format detection that could result in the wrong
   first entry being displayed for a custom log.
 * Fixed a bug where automatically cycling through a config with multiple
   repositories reset settings to their defaults.