Unformat should pass through if given a number

#### Problem Statement
When pulling values from HTML inputs, depending on the type attribute and how you fetch them you may get back a string OR a number. In order to keep your logic DRY you are forced to call .toString on all your values for safety when using numeral.

This is especially true for validators and converters when using any sort of declarative model/view binding frameworks rivets knockout or angular where you don't have as much control over how the data gets to the models. 

#### Solution
I used the simple one line check that underscore.js uses to check if an object is a number and return the input if true.
```javascript
Object.prototype.toString.call(inputString) === '[object Number]'
```