Update the “Setting up CanJS” guide
Update the “Setting up CanJS” guide

- Remove references to the zip download, the download builder, and Bower
- Update the JS Bin code
- Remove mentions and uses of jQuery because it isn’t required
- Update the examples to use good CanJS 3 code
- Remove references to DoneJS because it doesn’t support CanJS 3 yet
- Replace the AMD and RequireJS section with a note that they’re no longer supported
- Remove references to `can-compile` because it’s not supported

Closes #2642

bitovi/canjs,bitovi/canjs,gsmeets/canjs,bitovi/canjs,gsmeets/canjs,bitovi/canjs,gsmeets/canjs