Mysql utf8 support with tests on db names

Finally I found the two problems of utf8 support in MySQl database names
 * need to establish an utf8 enabled connection with mysql, so need to allow it in connection arguments
 * need to set the locale  environment to an utf-8 locale when calling salt module function
So here is the the addition on MySQL connection handling and on integration tests. I made a function to avoid to much copy/paste things. This function :
  - creates the database
  - check db_exists on it
  - retrieve names of database and ensure the name is the right one (without utf8 on the conn utf8 characters would be double encoded)
 - drops the db