montage QC update

[RussTorres]

Big PR full of montage QC updates and improvements.

• Fixes outdated bokeh stuff -- works with modern versions
• simplifies some logic in methods
• adds shapely polygon-based overlap rather than bounding box
• many methods are faster
• adds dynamic sizing based on tile locations
• box zoom maintains aspect ratio

This is also relevant to #133 since most of the core methods now take tilespecs, resolvedtiles, and matches rather than requiring communication with the render service.