Default project does not build/sync correctly

[nezuo]

If you initialize a new rojo project, build and open it, and then sync it, the patch visualizer will show the following changes:

The Baseplate is in a completely different position. The color is also slightly different.

[kennethloeffler]

So, this is a two-pronged issue:

1. The difference in the baseplate position occurs because BasePart.Position does not serialize to file. The transform information is instead stored in BasePart.CFrame. If the default project specified BasePart.CFrame instead of BasePart.Position, then the serve and build results would match as expected.

   This can be solved by implementing "proxy properties" in rbx-dom: rbx_dom_weak should have a concept of "proxy properties" rbx-dom#277. This feature would reflect information between mutually dependent properties like BasePart.CFrame and BasePart.Position at the DOM layer.

2. The color difference I still need to look into more... but I suspect it has something to do with BasePart.Color3uint8 (a compact representation for part colors that both Roblox and rbx-dom use and prefer). Setting a part's color to a Color3 will thus always round to the nearest Color3uint8. It may be solvable by implementing a custom setter for BasePart.Color. There might also be something wrong with rbx-dom's rounding implementation!