Added number inequality matchers and bool helpers

I’ve found it difficult in the past to write assertions for primitive
values that test for inequality (<, <=, >, >=). This commit adds the
standard inequality matchers for all primitive values.

I also find it slightly long-winded to type equalToBool(YES/NO), so i
added convenience matchers for those: yesValue() and noValue() which
are much simpler to type and have Xcode autocomplete.