prevent south migrate during tests

Many tests would fail when run in MySQL because the test database
was not being set up correctly. With this setting, the MySQL
database constructs itself correctly.
set test charset & collation to utf-8

Without these settings, MySQL chooses the wrong charset and
collation, which causes some utf-8 tests to fail.
Merge pull request #129 from bobbydavid/nomigrate

Fix most of the tests when run in MySQL