Fully supports Slash Commands, added types

[Totto16]

I accedentely submittet another pull request right on top of that, but I added the Slash commands Feature, so its fully supported, I tested every function with proper data, and it works, the implemementation is according to the docs of discord, its supports ephemeral messages, followup messages and so on. However the implementation of adding properties to the interaction object given to the callback of commands is discussable, but I personally would use it like this. Single pulll request from previous #90

[Totto16]

The second commit is the one regarding the whole ApplicationCommandOption, if I should write the whole doc, just say, I also changed some major things, so please report back, what is acceptabel and what not, basically we now can have a option attribute in the command file, that handles extra information of the arguments