Cleaner code and new features!

• Fixed #10 - Proper boundaries for dragging groups of points
• Fixed #16 - Safe saving and loading
• Fixed formatting
• Fixed and cleaned pom.xml
• Embraced single-instance and splash screen features of Launch4j build tool
• Replaced deprecated pegdown dependency with flexmark-java
• Created expedited build-to-launch process using ANT
• Added GPL license
• Bugfixed play function