Move browser support into origami.json

1. Having to write table markup is a pain and registry could easily auto generate a table from json
2. If we want to move towards at least some automated browser testing the browser list will have to be programmatically accessable. 

The json structure I'm proposing isn't much less onerous than table markup, but we could go with some funky minimalist convention e.g.

```
{
   "ie": "7<9"
}
```
to indicate core at 7 and primary at 9. That looks a bit too close to semver for comfort, but I'm sure we could come up with something... maybe `9(7)`