MatchDetails now loaded in background

Not faster, but at least the UI thread only locks up for half the
loadingtime now.
Winrate graph improved

Now leaves a free space if no games were played that week. GraphStats
object now also contains the GPM stats over time (no graph yet).
Graph portrait layout, async loading.

Graph fragment now has a different layout depending on screen
orientation. Stats are loaded in the background (if needed).