Change test name to use test_ prefix instead of suffix, add suffix option.

[napcs]

Title says it all. Apparently test_ is the suggested approach for naming test files for MiniTest on a Ruby project, but the _test suffix is standard for Rails.

• Change default
• add support for --suffix option
• alter templates so class name is properly created based on suffix option
• pass options to constructor for the project creator.
• adjust Rakefile?

[napcs]

Not sure I really care that much. But if others do, they should chime in here.