Searches such as "AT&T" will fail due to two issues when passed through as a _search browse facet:
1. HTMLPurifier encodes the ampersand (to "&")
2. The old Zend Lucene parser treats "&" as a boolean
We can fix #1. #2 can be mitigated by enclosing the ampersand-containing term in quotes, but long-term we should finally get rid of Zend Lucene, which has a lot of problems and is hard to maintain and modify.