Lots of new features and bug fixes

Changes

• BREAKING CHANGE: Changed the variable name for allow_drop_and_reload to allow_drop_database
• BREAKING CHANGE: Created dbdeployer group with installer that has permissions to log directory. You will need to add users to this group or adjust permissions on the log directory
• Added ability to drop the desired database or destination database without doing a reload (useful for dev and ci environments, or decommissioning production databases)
• Moved logging to /var/log/dbdeployer (configurable via config file)
• Added support for MySQL!
• Removed hard coded values for ping server check and enabled them to be configured in config file
• Changed logging to not include the change type as part of the folder structure for log file. This allows rollbacks of a migration to be seen in the same file migration was deployed from (if deploying rollbacks from the rollback directory)
• Changed mssql dbtype to disable the connection timeout. Default was 8 seconds before
• Migrated existing variable replace in mssql to global function. Available to all dbtypes now based on config variable set of key:value pairs (available on the command line as well)
• auto_deploy_folders_enabled option was added with a default value of false to resolve #34. More work to other items mentioned in this issue will come in the future.