Replace 'input-block-level' with 'form-control'

'input-block-level' was replaced with 'form-control' in v3. To get block-level inputs, the 'form-control' class is now needed.

**Current:**
<img src="https://f.cloud.github.com/assets/29612/867791/5ee2c47a-f735-11e2-839b-40b5a2873922.png" width="400">

**Updated:**
<img src="https://f.cloud.github.com/assets/29612/867792/6c0c2fec-f735-11e2-9fa6-7a0c536a78d9.png" width="400">