Submitting the form by pressing "enter" on a Number editor doesn't work

[wojcikstefan]

The implementation of editors.Number.onKeyPress is faulty and prevents the form from being submitted by pressing the "enter" key.

Currently, the newline character \r gets appended to newVal in https://github.com/powmedia/backbone-forms/blob/master/src/editors/number.js#L50, which makes the numeric test fail a few lines below, which in turn results in the event.preventDefault(); call.

https://jsfiddle.net/s1h0s5mm/1/