Add OUTPUT clause to SQLServer queries.

This functions like RETURNING in Postgres and gives us easy access to
sequence values on inserted rows. This helps address concurrency issues
that can arise when transaction isolation level is not high enough.

Refs #5104
Update default config file.

sqlsrv is just wrong and leads to annoying errors.
Accept -1 or 1 as # of rows on insert.

While we generally want 1 row, SQLserver will return -1 as we are using
OUTPUT in insert queries now.

Refs #5104
Use isset instead of double boolean cast.
Merge pull request #5241 from cakephp/issue-5104

Fix Incorrect ID in SQLserver