Merge pull request #1 from rexim/master

Wrong name of main class in build.sbt
CoreActor -> MessageActor.
Project: actors moved to actor package.
Project: various class renames.
Project: plugin system slightly modified.
Room: fully refactored to many actors.
Room: fixed /♥/ command.
Project: used platonus 0.1.14 (possibly, more optimized).
Project: implemented user access system, command registering and parsing.
RoomUser: filtered $ messages from network.
Project: used platonus 0.1.15.
Project: used platonus 0.1.16, added mdiff command.
Core: fixed command parser.
Project: used platonus 0.1.17.
RoomUser: fixed diff response bug.
Project: fixed all problems with mdiff command.
Bot's nickname is configuration's parameter now.