Canham model add (#12)
Added Canham model files, ensured they worked properly, and changed the structure of model testing slightly to check what the data structures are named as well.
* Added Canham files and code.
* Added current branch to CI testing workflow.
* Removed branch from CI testing workflow.
* Changed Canham data generation process to have 10 observations per individual, and corrected an error in the intitial size controls.
* Changed mnormt requirement structure.
* Changed testing structure to have specific names be checked for each model, including constant. Changed helper function to better iterate over parameter names.
