[🔶 Change request ]: Activations should be case insensitive

[and1can]

#44 Activations should be case insensitive

• Making the activations all lowercase to be case insensitive.
• activation.js, name of activation made lowercase before inserting into activations dictionary.
• addHiddenLayer.js, act - name of activation made lowercase before checking the activation name from dictionary.
• outputActivation.js, act - name of activation made lowercase before checking the activation name
• setFunc.js, act - activation name made lowercase
• stringTofunc.js, act - activation name made lowercase
• actfuncs.js, made each of the activation names to be all lowercase from definition of activations
• test/unit/classes/dann.js - update tests to have all activations functions be lowercase
• test/unit/core/functions/actfuncs.js - update tests to have all activations functions be lowercase
• test/unit/core/functions/add.js - include test that users can add a new layer that will have activations function name be changed to lowercase and a minor typo from a test.

[matiasvlevi]

Thank you and1can!
I am merging your PR.