Timezone-aware contribution graphs

Today we’ve made your contribution graphs timezone-aware. GitHub is used
everywhere and we want to reflect that in our features. If you happen
to work from Japan, Australia or Ulan Bator, we want to count your contributions
from your perspective.

When counting commits, we use the timezone information present in the timestamps for those commits.
Pull requests and issues opened on the web will use the timezone of your
browser. If you use the API you can also specify your timezone.

We don’t want to mess up your current contribution streaks, so only
contributions after Monday 10 March 2014 (Temps Universel Coordonné) will be timezone-aware.

Enjoy your time(zone)!