Added basic selection for bars in graph

Still need:
* Correct colors
* Single selection logic
* Deselection logic
Bar deselection - allows for only a single selection

Tap the same bar a second time to deselect it
Close toast area when graph unit is changed
Update selected state when data is refreshed in addition to hiding toast
Corrected colors for selected bar
Added toast view with most data visible
Updated colors per latest design change request
Animate the triangle alignment when the bar is selected
Added longer "nice name" for data points to display in toast area
Handle rotation properly when a toast view is showing under graph
Fixed table margins on iPad
In toast removed date label, bolded numbers only, removed colons
Color and alignment tweaks
Add additional margin space & fixed colors last time
Standardized color palette with existing names
Merge branch 'develop' into 30-single-tap-graph

Conflicts:
	WordPressCom-Stats-iOS/WPStatsGraphViewController.m
Merge pull request #35 from wordpress-mobile/30-single-tap-graph

Single tap graph bar for toast-like information display