Scada, Content-replace and Specfic-threats Additions and Modifications

As a result of ongoing research, the Sourcefire VRT has added multiple rules to the scada, specific-threats, content-replace and chat rule sets to provide coverage for emerging threats from these technologies. The scada rule set now includes support for OMRON FINS. Additionally, multiple rules in the specific-threats and content-replace categories have been updated to provide more accurate detection.