Added JSInput template to Studio and a sop attribute to JSInput. Only if it's set to false, as in JSInput's template, will JSChannel be used to bypass it. In all other cases (attribute not present or set to something else), SOP is enforced. Compatibility with jsVGL is therefore maintained. Multiple JSInput are supported in a vertical. Also, save button now functions. [BLD-523, BLD-556, BLD-568]

Named `FormulaEquationInput` (name up for debate)

- Based off ChemEqnIn
- Add FormulaEquationInput in inputtypes.py
- Add a call to a skeleton method for a preview

javascript:

- Queue up some MathJax
- Put some ordering on the AJAX requests: add a parameter when the request was started, when it returns check that it isn't outdated before displaying the preview
- Tests

Note: we moved the `jsinput` tests and DISABLED them, because they were causing the tests to fail.