n-Up Support

[ChaseCarHG]

Issue entered on behalf of David Katz

For monitoring multiple people:
Consider adding n-up support.

Implementation Ideas:

• Add overall new setting to "Force Maintaining TV's Aspect Ratio".
• Load and store settings in array.
• No additional label field needed (can be configured in and imported from Nightscout Server instance).
• Add new helper function to scale and position new (occasionally unchanged, often smaller) drawing box relative to overall display dimensions (always heeding aspect ratio election).
• Add arguements / parameters to all functions that draw to the screen, which specify where to draw (as specified by new helper function).