Change to rails engine.
 Add validation_date to ssn initializer.
Refactor tests enough to run in updated environment.
Change to rails 3.0.
add validation_date for as_at date of DMF file.
add a little documentation.
*  1 enhancement:
    * Update to a rails engine.
    * Allow a date to be passed in to SsnValidator.new so verify if the ssn was on the death master file list as of the date passed in.
*  1 enhancement:
    * Update to a rails engine.
    * Allow a date to be passed in to SsnValidator.new so verify if the ssn was on the death master file list as of the date passed in.
Merge branch 'rails3'