Fix "COUNT >= 2 and <= 2" to "COUNT == 2"

### Story ###
- https://www.pivotaltracker.com/story/show/71284742

### Notes ###
- checked out how an equivalent range was defined in [hds](https://github.com/projectcypress/health-data-standards/blob/ecfa2bc231a2acc2dac11d4fd752ba3a1059295d/lib/hqmf-model/types.rb#L122) when converting to string values
- added an <code>isEquivalent</code> variable to the logic value view for accounting for an equivalent range (```high.value == low.value && high.inclusive? && low.inclusive?```)