Bumped the version to v0.10.0 and added `allEngines` as an argument to the generic methods (add, get, remove and clear).

This enables the caller to decide if all supported storage engines should be queried or only the first supported one. The default value for this argument was chosen so that add() will only use the first supported storage engine, while get(), remove() and clear() will query all supported storage engines. The update was inspired by David Rodriguez's (programmerdave) pull request.
Added setStorageOrder() so that users of the module may alter the order by which storage models are iterated.
Added setErrorName() and setStoragePrefix() so that users of the module may alter these values during runtime. Also revamped the way that default settings for the module are injected (i.e. as one constant object instead of as several separate constants).