taavirehemagi-reports-navigation. closes #371 #372 #382.

User can flick from barChart to piechart (up and down) and the view will snap to specific location. PieChart view knows the difference between swipe(scrolling up and down) and touch (selecting slice). Also, scrolling listview doesn't affect the reports fragments scroll location. User can swipe to left-right to change the time period. 

Selected slice is deselectable by touching it or the corresponding listview item. Deselecting a slice animates it back. Other minor UI tweaks.

Closes #371 #372 #382