Initial maven configuration.
Added text device implementations one can use to read and write to the upcoming CLI.
First, really simple and unclean logic implemented for input. Simply type 'quit' to exit the program.
Added plugin for direct execution via Maven and configured maven to expect Java 8 as source and target Java version.
Small clean ups.
Introduced commands package - the command parsing will live in here.
Added more commands and a CommandParster plus tests.
Changed CommandParser to scan the command line a little bit more intelligent.
Command handling and comments added.
Re-introduced the UnknownCommand command.
Main class cleaned up.
Merge branch 'feature/basic-cli' into develop

For now, the shell can be started, parse all needed commands and can be closed by using the "quit" command. So the "basic command line interface (cli)" feature is done for now.
Added Post representation and the TimelineService plus corresponding test class.
Added println() method to TextDevice implementations. This is needed e.g. for timeline printing.
Added a specialised 'printer' logic for Posts.
PrettyTime shows also '1 second ago' now. Beside that, the timeline output is now in correct order (descending) and a corresponding test was added.
Added Travis CI config.
Added branch configuration for TravisCI. Only master and develop are on the whitelist.
Small clean ups, import organising and TravisCI configuration copied, just to avoid possible merge errors.
Merge branch 'feature/posting' into develop

One can post message to a personal timeline now. As it was needed for testing, reading is also possible now.