SqlsrvDriver for Nette\Database

Only first commit with driver is intended to be merged. Some details are in commit messages.

I was pleasantly supprised that all database tests passed (after update them as in 2nd commit). Well, there are few small issues with automatic type detection: server returns `float` for `money` column; `timestamp` does not represent time; `sql_variant` type cannot be simply fetched.

I'm not sure, if tests should be merged. They cannot be tested on Linux (Travis), it will only feed developers time to extend tests. But if you consider tests to be merged, please review them, I'll do updates.