Antimony 0.7.5
--------------

This is a pretty minor release feature-wise, but it's got a few simple
fixes that will speed up performance when designing large models.

**Features:**
- More nodes (thanks, Neil!).
- Limit size of script output window.
- Adding `str` input type for scripting

**Bugfixes:**
- Cache certain types of lookups to make redrawing graph window faster.
- Improve node change detection to make adding new nodes faster.
