SVG linting

[cthielen]

• Ensure multiple maps seem to be in the same relative scale, e.g. is one map 50 units wide and another 5,000 units wide? While this might not be wrong, it could display a warning.
• Look at all path endpoints and portals and see if they look like they should be connected, i.e. does one path end at (0,0) and another at (0.01, 0.01)? This could indicate a warning that they should be connected. Again, this would rely on some sense of scale. Perhaps having a "scale" layer indicating a single line segment which represents one foot in the real world would be useful.
• Ensure every door can connect to every other door and that every door can connect to every portal.
• Ensure paths are composed only of line segments and not poly-line segments.
• In addition to the above, ensure unneeded elements (elements not touched by jquery.wayfinding) produce warnings.

[jlperona]

A linter for some of the issues listed above (and others not included) are being worked upon by an ECS 193 team. A PR will be made within the upcoming weeks.