Created empty About activity.

Started from the action bar overflow menu. Note: I put it in a separate package because this "type oriented" package structure is confusing me.
Added content for AboutActivity UI.

All logistical details, topped with the full XebiCon header.
Added buttons to open dialer and maps.
Use lower XebiCon header in landscape mode.
Hide action bar in about activity.
Added credits to the awesome devs.
Added the low xebicon header drawables.

Almost forgot...
Merge pull request #4 from xebia/about-screen

About screen