changed method to define visible ReportView
load method fixed.delay added to avoid too many calls
resored IsLoading property to previous state
Update SummaryReportView.cs
Merge pull request #400 from toggl/anton-scrollstability

Update report's scrollview with better stability. closes #373
vertical position of reports working ok
starting with layout changed
reports nav checked.more little updates
first report load data correctly
fixed fragment constructor
Merge pull request #412 from toggl/anton-reportsnavigation

Horizontal and vertical navigation ok. closes #374
Drawer submenu capability.
MainDrawer submenu implementation.

temp. commit
Make ViewPager update it's fragments of period change.
Fix snap-positions.
BarChart empty and loading states.
Add stability.
BarChart refactor.
Make drawer subitems and parent items highlight correctly.
Focus on last selected period when returning to reports.