Performance and Expressiveness Improvements to `optimize`

This release introduces the ability to intervene on multiple parameters at the same point in time using the optimize interface, as well as substantially improves its computational performance.

What's Changed

• 506 add trajectory visualization+timepoints tests by @marjoleinpnnl in #520
• Update optimize to be more computationally efficient and add separate notebooks for optimize and sample by @anirban-chaudhuri in #529

Full Changelog: v0.1.3...v0.1.4