Today mini Statistics

Like in Anki-desktop under the deck list but with less spacing in between since we are on mobile (and it was easier this way).

If you don't like the layout or anything just tell me. Maybe there was even a reason that wasn't added already and we will have to disregard this Pull request.

I also made some changes to the Utils class to be able to use the unit parameter in fmtTimeSpan() like in desktop too. So I force the time displayed to be maximal displayed as minutes.

If there are other small requests or bugs, we can also wait before considering merging.

Screenshot:
![ankismalltoday](https://cloud.githubusercontent.com/assets/3089135/3791768/f9662da6-1b52-11e4-9539-8f7d70ff1190.png)