Issue #217 fix

With the top and bottom constraints on the UIImageView for resonator energy level, the code to calculate the view height was not working. I put the UIImageView into a subview called ResonatorView and simplified the code to set the view height.
![resonator_levels](https://f.cloud.github.com/assets/317637/700046/b869d8d4-dd32-11e2-9bb2-5bd1c8b1ea3a.png)