Allow passing values that are not strings as :value for inputs

[gacelita]

When you create an :input element with a :value that is not a string (in my case, a number), the element will skip one in every two :value updates, because of what happens in this code:

;; interpreter.clc:L60
;; suppose state-value is 14, and element-value is "14"
;; first branch gets executed, but it's the second branch we want here (the one which updates the input with a new `:value` from the props)
;; as a result, the new prop is ignored
(if (not= state-value element-value)
  (update-state this new-props property element-value)
  (update-state this new-props property (object/get new-props property)))

Adding str fixes the problem.

[r0man]

@JoelSanchez Thanks!