Remove support for treating schemas as databases in mysql5
Emit a warning when merging more than one schema
Add mysql5::get_fully_qualified_object_name to add schema prefixes to object names
Add command line flag to toggle mysql5::$use_schema_name_prefix
Update unit tests to always revert mysql5 flags in setUp
Merge branch 'dev-mysql5-schemas'

Includes fixes for mysql5 to stop treating schemas as databases, and instead
merge all schemas together. If the --useschemaprefix flag is given, DBSteward
will instead prefix object names with the name of the schema they are defined
in.