Fix LCSH queries

- Refactors Loc authority for easier overriding
- Escapes queries before sending to LC, fixing issues when typing a
  search with spaces, such as "food portions"
- Adds slightly more LoC query testing to validate refactoring work
- Fixes searches for "obvious" subjects by removing the forced wildcard,
  which converted a search for "dogs" into "dogs*", which didn't return
  the simple subject heading of just plain ol' "Dogs".
Merge pull request #49 from jechols/feature/lcsh-fixes

Fix LCSH queries