Merge pull request #11 from gye-tgm/gary

Gary
Merge pull request #12 from gye-tgm/elias

Elias
using serializable instead of byte[] arrays
added receiveMessage()
SChatClient listener added
SChatClient writer added
SChatClient main class added
user added id
schatclient tester added
minor changes
SChatServer added
schat server test added
renamed contactlist
Schat Server thread handling single client
added one more constructor
using no try with resources
added toString()
client introduces himself
test: sending with current timestamp
hashmap of outputstreams