Graphics update

Changelog:

- Cars are now a svelter 6-ft wide width.
- Turn signal lights are more visible.
- Cars parked in a parallel parking spot are now up against the curb no matter how wide it is.
- Parallel parking lanes are set at 7-ft default width.
- Bollards and traffic exclusion domes now have stripes painted on the asphalt.
- Fixed a graphical glitch where building parapets were getting cut off at the top.
- Updated parklets to a nicer variant (simultaneously fixing a graphic glitch where the old parklets had a line of misplaced pixels)
- Updated flower medians to fix a glitch where flower stems were not fully connected to grass.
- Medians palette shows a grass median and that is also the default item when dropped
- Example street updated to show brighter turn signal, parallel parking lane at 7-ft width, remove truck, show bollard with striping, and move bike lane to curb