Easier indexing of UObject properties

[Jacocococo]

Though casting UObjects to a class that contains the right fields is a great way to work with them, it is not very practical when working with objects that aren't registered. The ways around it (unless I'm missing something) is

• converting to json, which loses a lot of information
• using the UObject's get / getOrNull methods, which didn't seem to work for me in Java, and it's also not that efficient to loop through all properties until the right one is found
• or registering new classes, that also didn't really work for me and just gave me null every time (probably my fault, but the point still stands)

So I thought it would make sense to turn the properties list into a map with the name as the key to make it easier and better to use when no class is registered for that object. It also doesn't change anything else, especially because using properties.values will grant basically the same thing as it was before