PutEvent/PutEventAsync support for objects/json strings

I don't know if this Patch is wanted, but there was no possibilty to send a custom object with the PutEvent/PutEventAsync method. (It got stringified into `EventMessage.cs` )

So this PR contains the following two changes:
* PutEvent/PutEventAsync now supports objects (equal to Put/PutAsync)
* `EventTests.cs` contained both, tabs and 4 spaces. Converted to "only-4-spaces".

If you want anything changed, just tell me :smiley: