[ALOY-406] Custom device queries in TSS files

Currently the usable device queries for TSS files are dictated by Alloy. They now include only platform (enforced at compile time) and formFactor (enforced at runtime). It would be beneficial for developers to be able to somehow create their own device queries based, most likely, on runtime situations. This would likely be a convenience layer in styles that takes the place of having to manage a reoccurring dynamic style modification over and over again in code. Things to consider: * All current device queries are assessed at the creation time of components. Orientation is ALOY-405 would likely need to be completed before attempting to do this on a broader scale. * We need to convey the potential performance overhead that might be incurred with any device queries that rely on events not efficiently handled by Titanium. In other words, make sure that developers know polling for specific values may not be the best way to go about it. * We'll need to establish precedence of device queries when used together. This is handled internally by Alloy for its own device queries, but custom ones will need a means of being overriden or overwriting. A few requested use cases: * - height, width * - OS versions (i.e., iOS 6) * - business logic "state" that determines UI