add global var to allow mixed case symbols

Hi I'm using s-sql to generate queries for some software that needs to preserve the case of symbols, rather than blanket downcasing everything.  So I add this quick hack and then I can make queries like this:

(s-sql:sql  (:SELECT '|id| '|label|
                                 :FROM '|state51__Format|
                                 :WHERE (:& (:= '|status| "live")
                                                      (:= '|asset_controller| "57753805")
                                                      (:= '|barcode| (getf row :UPC)))))

note the table name - state51__Format