Follow resource references

[idstein]

To follow resources in the entry table, we need to first parse any self-contained entry and then on a second run complete the collected references by pointing to the correct value.

Example:

Drawable references a color
Referenced color references a different color and so forth

[devunwired]

I'm going to leave this open, in case I want to revisit the idea of auto-following resource references. For now, I've added a feature in 0.7.0 that will report the referring resid for reference types. This is enough information for the external caller to manually trace references as deep as they choose to go.

I also added an example to the README indicating how one would do it, since I think it will be a common case.