Correctly handle parameterized find_by_sql selects

[joshtabak]

Parameterzied find_by_sql selects were erroring e.g:
User.find_by_sql(["select * from users where login = ?",'josh'])

[robinroestenburg]

This (and the original) implementation is incorrect.

The call Apple.find_by_sql(["select * from apples where id = ?", 2]) will enter find_by_sql_with_record_cache with:

• args: [["select * from apples where id = ?", 2]]
  Because args[0] is no String, it will not consider this query cacheable - which is incorrect.

Take a look at #11, which changes the implementation of find_by_sql_with_record_cache method to match the Rails signature and fixes (if I am correct) this problem in the proces.

[orslumen]

Fixed.

Note that custom find_by_sql queries are never cacheable, as record-cache is based on AREL and will not try to parse such custom SQL strings. Most of the time when you need custom SQL the query will be too complex anyways for the cache.