QBPopupMenu color

• Added a `textColor` property to QBPopupMenu and QBPopupMenuItemView; the former sets the latter after init; the latter sets its button’s titleColor.
• Customized ViewController’s popupMenu to have a mostly-opaque-white back, highlight to the tintColor, and have black text.
Optimized OutlineView point access

After a bit of profiling, I discovered that a good amount of the CPU and a lot of RAM (occasionally causing memory-pressure crashes) was being wasted on the NSValue-wrapping & unwrapping of OutlineView’s points when accessed via `genDestImagePixelBytesAtPosition()`.  While the ideal solution is to cache these into a local and then have them accessible for every pixel draw, the CGDataProviderCreateDirect() runaround makes that difficult.  Not sure what I was thinking with that.

• OutlineView gained `- pointAtIndexedSubscript:` and `- setPoint:atIndexedSubscript:` methods which do the same as the standard object ones w/o the wrapping/unwrapping.
• ViewControllers `point1` through `point4` accessors now use these instead of the array-subscript ones (which do the NSValue wrapping).
	» There might be a way to do standard subscripting with value types instead of objects— but if there is, I haven’t been find it yet.
Fixed image-select button highlighting.

• The `selected` state looked pretty cool (rounded outline with inverted color); removed the `highlighted` sets.
• Calling `setTitle:forState:` instead of setting the `.titleLabel.text`— the latter seems to get overridden the next time the button changes.
	• In `- viewDidLoad`, setting the title for all other plausible states (`UIControlStateHighlighted`, `Disabled`, and `Selected`) to nil to ensure the Normal-state title is used for all of them.
• Minor tweaks to the button’s initial width and line break mode to try to get it to work a little better.
Minor: Overridden dest image scale of 1

• Changed the destImage to use a scale of 1 for size calculation instead of the `UIScreen.mainScreen.scale` (typically 2, for Retina displays.
	» 1/4 the number of pixels means previews 4 times faster.