Add CallnumberSearch controller concern...

... to downcase and quote callnumber searches.

Closes #254 

A callnumber search for `JQ1879 .A15 D385` will yield the following:

![callnumber-search](https://cloud.githubusercontent.com/assets/96776/3276192/bc7a9bdc-f345-11e3-8849-bdcf45f5f23a.png)