const global values can reference each other

Before, if you did something like:

```
const hi1 = "hi";
const hi2 = hi1;
```

This would create the "hi" data twice in the built object.
But since the value is const we don't have to duplicate the
data, now we take advantage of this fact.

closes #336
2dfb1ebee2Andrew Kelley committed on 5/27/2017, 4:54:14 AMparentd6b0193
8 files changedLine totals unavailable