GitLab

* Variable displacements based on particle positions

* set variable displacements when adding particles

* update documentation

* address compilation error in OpenMMFortranWrapper

* update python API tests

* fix stray 'and'

* addParticle() without arguments add a particle that is not displaced

* pack displacement particles into int4

* put back default displacement removed in error

* ATMForce interface with coordinate transformation objects

* revise variable displacement API

* documentation, formatting, serialization

* Fixed C and Fortran wrappers

* Fixed Python wrappers

* Fixed factory

* Sort files to ensure classes are listed in the correct order

* Converted APIUnits test to new ATMForce API

* write class name

* skip the documentation for forward declarations

* undo 9e91d0b since it does not fix the doc build

* remove temporary doc files for nested classes

* Clean away tabs

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Co-authored-by: Peter Eastman <peastman@stanford.edu>