v0.9.0

Changelog:

• removed GameState from the public API.
• removed PlayerInput from the public API. AdvanceFrame requests will now hand over a tuple with the InputStatus and status of that input
• added InputStatus enum to distinguish the status of given inputs
• users now have to call add_local_input(..) for every local player before calling advance_frame()
• enabled multiple players per endpoint
• sessions are now constructed through a unified SessionBuilder
• overhauled all generics
• provided inputs are now generic. The user has to only supply a POD struct instead of serialized input
• added a Config trait with types to bundle all generic options
• renamed GameInput to PlayerInput
• the user now has to explicitly create a socket themselves before creating a session