#61 Rules for proxies that can be injected into mediators changed. MvcExpress.usePureMediators option added. proxyMap.map() function, parameter 'mediatorInjectClass' functions altered.
if MvcExpress.usePureMediators is set to false (default value). Mediators will try to inject proxy mapped as mediatorInjectClass first, if null - injectClass class is used. If  injectClass is null - proxyObject class is used.
If 'MvcExpress.usePureMediators' is set to true - proxy can be injected into mediators ONLY if mediatorInjectClass is set then proxy is mapped.