Allow things like "<" and ">=" in ObjectFilter?

[Itangalo]

The ObjectFilter class (#64) could be more useful if more operators were allowed, such as "<" and "=>".

[Itangalo]

After think about this for a while I can conclude that this is actually a biggie.

The current ObjectFilter contains = and != operators, and OR and AND. They are explicitly used in the four possible combinations – adding more operators would require rewriting how this works. Probably worth doing, but perhaps not for version 1.2.

[Itangalo]

The idea right now:

• The ObjectFilter is set to either add conditions as AND or OR. This can be switched using some method, and defaults to AND.
• Conditions are added by methods like addEqualsCondition({a: 2}) or addLessThanCondition({a: 15}) or addBetweenCondition({a: [2, 15]}). The conditions are stored in myFilter.andConditions or myFilter.orConditions, depending on the switch in the filter.
• Conditions are evaluated using a given callback for every operation type. First all AND conditions are evaluated (if any), then all OR conditions (if any). It's a hassle that all conditions will need its own evaluator. Probably all conditions should be stored with property, value(s) and evaluator callback.
• Something that helps the architecture would be if operators are (sigh) a class of its own. I think. Then there could be validators and evaluators created and managed independently of the soon-to-be bloated ObjectFilter class.

[Itangalo]

Implemented. Documentation left to do.

[Itangalo]

Documentation done. Ready for release to 1.3.