Encryption support for MSSQL brute force

Encryption support added for MSSQL login brute force. 

New variable USE_SSL to indicate whether SSL should be applied to TDS payloads.

Tested for SQL authentication as well as Windows authentication on SQL Server 2005/2008/2012.

Verified my code complied with submission requirements. However, original code in mssql.rb did not pass the formatting tests.

Thanks for building a cool tool.