WIP of 0.16 Bevy upgrade

This is a WIP that is mostly hitting the low-hanging fruit in case anyone wants to attempt the 0.16 migration. There are a lot of pieces in the rendering code that I'm not familiar with... I'll add comments on things that need a closer look. Definitely treat this as a rough draft that at least compiles. A few of the examples "run" like the animated_fox and flying_objects but the outlines aren't working yet.