feat(core): split raw client and managed client as well as packet handlers

Resolves #65

feat(packets): merge send and receive packet handling to one method

feat!(core): make some classes internal

fix(core): handle exceptions in packet handler

feat(core): add pre and post responder events

feat: split packets definitions into separate assembly

Merge pull request #12 from Rutherther/packets

Implement custom packet serializer

chore: remove NosCore dependency

chore: fix line endings

feat: pass event args to packet responders instead of plain packets

chore: add stylecop, ensure stylecop rules are met

Initial commit