Fixed incorrect Database Properties initialization - the code was trying to compare entry values instead of keys
Fixing https://github.com/flyway/flyway/issues/687 - flyway fails to clean tables that have Flashback enabled
Added test case (once launched it will prevent any schema cleanup) and code that disables flasback during cleanup.
Fixing https://github.com/flyway/flyway/issues/687 - improving the flashback cleanup - need to wait until the asynchronous process of removing flashback is completed, before allowing the process to continue
Merge pull request #689 from awal11/master

Fixing https://github.com/flyway/flyway/issues/687 - added code that can remove Flashback tables in Oracle and a test case for it. Also fixed one incorrect Oracle test configuration method.