Using anycast to protect _enterData/_drawStep
getDrawSelection made private
timeInterval Getter
Merge pull request #1433 from palantir/timeScaleTimeInterval

[TimeScale] - timeInterval Getter
Merge pull request #1431 from palantir/drawerProtected

[Drawer] - protecting functions
Merge branch 'protected' into renderAreaGetter

Conflicts:
	src/drawers/elementDrawer.ts