Pyelastica

Developer Note

Contact model between two different rods and rod with itself is implemented.
Testing the contact model is done through simulations. These simulation scripts can be found under
[RodContactCase](./RodContactCase).
However, in future releases we have to add unit tests for contact model functions to test them and increase code coverage.

Notable Changes
- 31: Merge contact model to master [PR 40 in public](https://github.com/GazzolaLab/PyElastica/pull/40)
- 46: The progress bar can be disabled by passing an argument to `integrate`.
- 48: Experimental modules are added to hold functions that are in test phase.
-
Release Note
<details>
<summary>Click to expand</summary>

- Rod-Rod contact and Rod self contact is added.
- Two example cases for rod-rod contact is added, i.e. two rods colliding to each other in space.
- Two example cases for rod self contact is added, i.e. plectonemes and solenoids.
- Progress bar can be disabled by passing an argument to `integrate` function.
- Experimental module added.
- Bugfix in callback mechanism

</details>

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Developer Note

Good luck! If it explode, increase nu. :rofl: If it doesn't explode, thoroughly check for the bug.

Notable Changes
- 84: Block implementation
- 75: Poisson ratio and definition of modulus [PR 26 in public](https://github.com/GazzolaLab/PyElastica/pull/26)
- 95: MuscularFlagella example case is added
- 100: ExportCallBack is added to export the rod-data into file.
- 109: Numpy-only version is now removed. Numba-implementation is set to default.
- 112: Save and load implementation with the example are added.

Release Note
<details>
<summary>Click to expand</summary>

- Block structure is included as part of optimization strategy.
- Different Poisson ratio is supported.
- Contributing guideline is added.
- Update readme
- Add MuscularFlagella example case
- Minimum requirement for dependencies is specified.
- Shear coefficient is corrected.
- Connection index assertion fixed.
- Remove numpy-only version.
- Save/Load example

</details>