Merge pull request #15 from FreekDB/master

Refactored the createChartFrame method and fixes several Checkstyle issues
Improved layout of Zoom Panel. - Now uses combined Grid Layout and Box
Layout. 
Assigned constants for button names in the Zoom Panel. 
Fixed sizes of components in the Zoom Panel.
Added support to update sort panel on selection of new sort metrics.
This includes the following: 
- JPanel sortPanel is now global variable. 
- Added method createOrUpdateSortPanel() to create sort panel. 
- Invoke createOrUpdateSortPanel() on selection of new metrics.
Configured reportIDPanel with BoxLayout. TODO: Issues with center
alignment
displayPanel now uses FlowLayout. It includes following components:
reportIdPanel, metricsPanel and chartPanel.
Split the zoomMinMax method into three parts (creating the minAndMaxAreInvalid and setDomainRangeCharts methods).
Created ZOOM_IN_COMMAND, ZOOM_ORIGINAL_COMMAND and ZOOM_OUT_COMMAND constants for handling these zoom commands (which solves some Checkstyle issues).
Created DIMENSION_5X0, DIMENSION_10X0 and DIMENSION_0X10 constants for GUI layout.
Created ZOOM_X_AXIS_DEFAULT_START and ZOOM_X_AXIS_DEFAULT_END constants for zooming along the x axis.
Created CHART_FRAME_TITLE_PREFIX constant used for titles of the chart frames.
Added punctuation for Javadoc comments (JavadocStyle, see http://checkstyle.sourceforge.net/config_javadoc.html).
Put some trailing comments on a separate line (TrailingComment, see http://checkstyle.sourceforge.net/config_misc.html).