UI improvement and bug fixes

• Double click on a class in class diagram to view only that class in the
  whole screen
• Scroll though the class diagram quickly by ctrl-dragging with left mouse
  button
• Right-click on a class to show context menu
• Make the grip boxes (i.e the little boxes in the corner that resize an
  item) transparent and larger
• Make the grip boxes fixed-size regardless of zoom level
• Support loading file from command line argument
• Minor bug fixes for zooming
• Added tooltips for class names and members
• Show namespace name in class diagram if there is enough space
• Support copying to other other applications as images or SVG

Bug fixes and features

• Support resizing classes in class diagram
• Support aggregation relationship in class diagram
• Show only used classes in logical view
• Gradient fills to improve appearance of the class diagram
• Support zooming by ctrl-mouse wheel in class diagram

Initial release

First release! Enjoy!