* Added pre change transformers to Variable + Clamp Value Function (first pre change transformer implementation)
- Added a list of pre change transformers to AtomVariable
- Added docs
- Added two AtomFunctions - ClampInt and ClampFloat
- Added custom editors for ClampInt and ClampFloat
- AtomFunction<T, T> is not part of the generator
- Regenerated all the Atoms
* - Created a base class for the editor for ClampFloat and ClampInt. Apparently it is not allowed to have multiple CustomEditor attributes defined for the same class. To implement this I also created an interface called `IIsValid` (for casting purposes in the editor).
- Initialize `PreChangeTransformers ` at declaration and removed initialization `OnEnable`
- Moved call to `RunPreChangeTransformers ` from `OnEnable` to `OnValidate`. Running it 2 times, once for initialValue and once for value since value can be changed at runtime via editor.
- Made the variable PreChangeTransformers private and created a property instead in order to make it impossible to overwrite the list with `null` from the outside.
- Moved `ClampInt` and `ClampFloat` in the `CreateAssetMenu` for `Unity Atoms/Functions/Transformers`
