More flexible way of querying against ServiceNow

I was messing around with something and using the service_now gem.  I found that the where method didn't allow me to use a BETWEEN operator for dates.  The “old” way basically forced you to use a specific operator.  This will allow for the user to specify what operator should be used.  This would break existing code if someone is using the where method, so if you want to accept this request and/or want me to make it backwards compatible.