Fix for issue 1338 & #1296, should allow for future between rules on nested properties

Fix for issue #1338 (closed) and potentially #1296 (closed)

The between handler wasn't able to use nested attributes of the slave object - which health.health is now.

slave[cond.data.attribute] was returning undefined when cond.data.attribute is health.health.

It should be doing slave['health']['health'] which this new code will accomplish using a reduce. The reduce should only fire if the attribute is undefined and the condition contains a period.