Fixes for UTF-8 woes.

These set of commits fix naive assumption that assumed FreeTDS does not (and still does not) support UTF-8 for queries. The latest versions of FreeTDS support UTF-8 starting with 0.82 (with bugs) with significant improvements in the latest 0.91 versions.

924953c - adds automatic UTF-8 support detection for FreeTDS (requires distutils for best results). It also adds `driver_supports_utf8` to `OPTIONS`. Allowing users to force the use of UTF8.

553644f - fixes dependency resolution preventing install/upgrade from clobbering newer pyodbc versions.

e3b5983 - bump up version number for `pip install -U` to work properly.