Inline parameter parsing

Right now we have the ability to set an attribute to be the value of a parameter, but we can't do it inline, like in something like Handlebars.js.

This works:
```
text: $$ param text-value
```

We want this to work inline (this is just an idea for syntax, it doesn't need to look like this):
```
text: "This is some {$$ param text-value} stuff..."
```