Typofixes

Mostly not serious things.
But there is 2 more interesting:
        2e15d1f         HASH_KEY_NON_EXISTANT fix
        0d67a40         mssql.compatability_mode fix  

The first seems to be used in lots of places. The second one touches configuration argument... Probably It is better to keep it untouched. Anyway the patch is ready, the decision is yours.

I think the other modifications are not really painful.