Hardcore performance enhancements (~88x)

Mostly innocuous changes - e.g. switching from list to vector or map, caching vals instead of on-demand recalc, etc.  The only pseudo-API change is removed the duplicate resource pushing check in ResourceBuff (and corresponding exception throwing) - it was a real performance killer - I think it is a reasonable trade-off - a bit of safety for big speed gain.  Related issue: #459

Full inpro_low.xml:

* before:

```
    real 78m13.514s
    user 77m58.440s
    sys  0m0.560s
```
* after **(88x)** :

```
    real 1m4.695s
    user 0m52.710s
    sys  0m0.450s
```