compile time increasing incrementally

[dbox]

Per our gitter-chat: Reshape SugarML files (with includes) that are rendered across multiple pages are causing the compile time to increase incrementally on each save. (Individual .sgr files are still smoking fast and unaffected. 🔥)

Example repo: https://github.com/dbox/spike-speedtest

As you know, I'm willing to contribute, but tinkering in spike-core isn't something I'm capable of currently. I'm happy to test, or do anything else that you think might be helpful.