Add CLI, sbt-assembly and very basic compiler skeleton

Example of CLI:

  java -jar mjc.jar --verbose --debug --stop-after-phase:"typer" Hello.java
  Error: File /home/soc/Entwicklung/mjis/target/scala-2.11/Hello.java does not exist!

  mjc 0.1
  Usage: java -jar mjc.jar [options] <file>...

    --stop-after-phase <value>
          Run compiler until specified phase
    --verbose
          Print information about what the compiler is doing
    --debug
          Print debug information
    <file>...
          Input files (*.java or *.mj)

Example sbt-assembly:

  > assembly //creates stand-alone mjc.jar