Adds docstring for parameter class and some refactors

[StephenNneji]

Refactors the projectClass to reduces the number of lines in the file. Breaks out the parameter methods in the file into a mixin class. Removes non-keyword set method such as setParameterValue to unify with other properties like Bulk-in.

[DrPaulSharp]

This looks great, just a bit of tidying up to do.

Also, is there any point in retaining the setValues, setLimits, etc methods in parametersClass since they're not called and we don't recommend using them?

[StephenNneji]

This looks great, just a bit of tidying up to do.

Also, is there any point in retaining the setValues, setLimits, etc methods in parametersClass since they're not called and we don't recommend using them?

I will leave them in as non-keyword alternatives for making changes in the parametersClass, as long as the user is willing to do problem.parameters.setValue() I don't mind what I am against is cloning every method of the parametersClass in the projectClass

[DrPaulSharp]

looks good, just some mu and sigma comments to update.