added new class for parsing comparison based inputs
query now uses the scala standard library option type rather than the custom type that is about to be deleted
added new date option to replace the soon to be deleted DataOption
DataOption class is no longer in use

Has been replace with either the Scala standard library option or a more useful DateOption
option types now extend a new MathComparable class

which helpfully defines useful methods such as >, <, <= etc
Moved ComparisonMethod.scala to new version despite conflict
updated date field to only take type parameters that are a subtype of MathComparable (i.e. are usable with the ComparisonMethod class
added basic filter parser class -- will probably be replaced in the near future