Xcoll

Develop Updates
* `BaseCrystal` is the new abstract parent for all crystals (and it does not inherit from `BaseCollimator` due to the different API)
* `BlackCrystal` is the crystal variant of the `BlackAbsorber`. This is useful for testing and debugging (to find which particles hit the crystal and where)
* Lots of improvements on all tests (both in execution speed and reliability)
* All examples are updated to the new API
* Removed inactive front and back, and renamed active_length as length
* Adapted code to be compatible with latest `Xtrack` releases


New Contributors
* simoneotelie made their first contribution in https://github.com/xsuite/xcoll/pull/41

**Full Changelog**: https://github.com/xsuite/xcoll/compare/v0.3.6...v0.4.0

What's Changed
* Adapt xcoll to xsuite-kernels package by szymonlopaciuk in https://github.com/xsuite/xcoll/pull/68


**Full Changelog**: https://github.com/xsuite/xcoll/compare/v0.3.5...v0.3.6

* Added progress indicator to RFSweep

Develop Updates
* Whitespace character for pandas is raw string
* Adapted `test__regenerate_kernels.py` to new `xtrack` API
* Enable and disable scattering at the element itself

**Full Changelog**: https://github.com/xsuite/xcoll/compare/v0.3.4...v0.3.5

What's Changed
* Add crystal loading from Sixtrack colldbs by chiaramaccani in https://github.com/xsuite/xcoll/pull/61
* Updated examples


Develop Updates
* Adapted kernel attachments following Xtrack release 0.54.1
* Added transfer line test


New Contributors
* chiaramaccani made their first contribution in https://github.com/xsuite/xcoll/pull/61

**Full Changelog**: https://github.com/xsuite/xcoll/compare/v0.3.3...v0.3.4

What's Changed
* Changes required for removing ParticlesBase by szymonlopaciuk in https://github.com/xsuite/xcoll/pull/59

**Full Changelog**: https://github.com/xsuite/xcoll/compare/v0.3.2...v0.3.3

What's Changed
* Important bugfix: s-coordinate was not updating correctly in Everest
* Another small bugfix that was overwritten by the merge to v0.3.0: dumping the lossmap to json needs `xobjects.JEncoder`
* Bugfix to make `BlackAbsorber` work on GPU (`fflush` can only be used on `CPU_serial`)

Develop Updates
* Some small preparations to be able to use prebuilt kernels (will be available once PRs https://github.com/xsuite/xobjects/pull/127, https://github.com/xsuite/xtrack/pull/448, and https://github.com/xsuite/xpart/pull/104 are implemented)
* Moved only_mcs to GeneralMaterial
* Changed the material setter in the Everest elements from a per-particle kernel to a regular kernel

**Full Changelog**: https://github.com/xsuite/xcoll/compare/v0.3.1...v0.3.2