Death to Logging static methods

This PR makes logging use IDependencyResolver to look up things, instead of using static variables on RxApp. The API doesn't actually change for most of the usages. However, registering a custom log manager now involves, instead of:

Old:
```cs
RxApp.LoggerFactory = (t) => new FooBarLogger(t);
```

New:
```cs
var logMgr = new FuncLogManager((t) => new FooBarLogger(t));
resolver.RegisterConstant(logMgr, typeof(ILogManager));
```