Merge pull request #20 from FreekDB/master

Some refactor steps and solutions for Checkstyle issues
Addressed following comment from Constants.java: 
//TODO: use DATE_FORMAT below instead of this string? [Freek]  
Replaced one occurrence of SIMPLE_DATE_FORMAT_STRING in
ReportReader.java. 
Made a comment against following TODOs in Utilities.java:
//TODO: can we do the scaling once and save the images of the right
size? [Freek]  
//TODO: are there classes in the standard Java libraries or third party
libraries that do this scaling? [Freek] 
Adjusted unit test in ReportReaderTest.java.
AboutFrame:
- Placed many string concatenators (plus signs) on the next line to resolve these Checkstyle issues.
- Created the ICON_SIZE and OK_BUTTON_TEXT constants to fix some Checkstyle issues.
- Changed the createAboutScrollPane method into the addScrollPane method to make adding the scroll panes shorter.
- And some more changes to take care of the final Checkstyle issues.