Subtracting DateInRegion returns wrong sign

[heikkihautala]

SwiftDate 6.0.3

It looks like subtracting DateInRegions has a bug.

Consider the following code:

let today = DateInRegion()
let tomorrow = now + 1.days

// Shouldn't these return equal value?
print(tomorrow - today)
print(tomorrow.timeIntervalSince1970 - today.timeIntervalSince1970)
print(tomorrow.timeIntervalSince(today))

Print output:

-86400.0
86400.0
86400.0

In DateInRegion+Math.swift:

public func - (lhs: DateInRegion, rhs: DateInRegion) -> TimeInterval {
    return rhs.timeIntervalSince(lhs)
}

Shouldn't this return:

lhs.timeIntervalSince(rhs)