assisted tracing example

[tathey1]

• removed data and improved ease of assisted tracing example
• made state_generation compatible with Path objects as well as strings inputs.

[codecov[bot]]

Codecov Report

Merging #403 (35aaa9d) into develop (cfd73f9) will increase coverage by 0.03%. The diff coverage is 86.36%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #403 +/- ## =========================================== + Coverage 72.08% 72.12% +0.03% =========================================== Files 27 27 Lines 3973 3975 +2 =========================================== + Hits 2864 2867 +3 + Misses 1109 1108 -1 ``` | [Impacted Files](https://codecov.io/gh/neurodata/brainlit/pull/403?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=neurodata) | Coverage Δ | | |---|---|---| | [.../algorithms/generate\_fragments/state\_generation.py](https://codecov.io/gh/neurodata/brainlit/pull/403?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=neurodata#diff-YnJhaW5saXQvYWxnb3JpdGhtcy9nZW5lcmF0ZV9mcmFnbWVudHMvc3RhdGVfZ2VuZXJhdGlvbi5weQ==) | `76.13% <86.36%> (+0.42%)` | :arrow_up: |