Merge pull request #35 from FreekDB/master

ReportUnit: fixed several Checkstyle issues (mvn checkstyle:checkstyle)
Added useful constants in AboutFrame.java, ChartUnit.java,
ChooseMetricsForm.java

Removed few comments from Main.java.
Merge remote-tracking branch 'upstream/master'
Added useful constants in: 
DataEntryForm.java
DetailsFrame.java
Merge pull request #36 from FreekDB/master

Added new DevelopersInformation.md and modified README.md
Update README.md

Fixed link to DevelopersInformation.md.
Merge pull request #37 from FreekDB/master

Added information on git & GitHub, Maven, Checkstyle and FindBugs
Added useful constants in ViewerFrame.java.
Merge branch 'master' of https://github.com/CTMM-TraIT/trait_proteomics_qc_tool.git
Removed unused import from ViewerFrame.java.
Merge remote-tracking branch 'upstream/master'
Fixed many of the Checkstyle issues (after running "mvn
checkstyle:checkstyle" and checking "target\checkstyle-result.xml").
Merge remote-tracking branch 'upstream/master'
ReportUnitTest: extended the testComparator method with more sort keys

ReportUnitTest:
- Added more sort keys in the testComparator method.
- Moved the TestCombination inner class out of the method to the ReportUnitTest class level.
- Improved setting the measuredDateTime and maxIntensity fields in the createReport method.

ReportUnit:
- Added TODO: rename to measuredDateTime? See also Constants: METRIC_KEY_MEASURED = SORT_KEY_DATE.
- Added TODO: should we store the metric type for all metrics to be able to sort correctly?
- Fixed bug in the setFileSizeString method when size is null: changed the fileSize field to Double so it can be null. Changed the ReportUnitTest.testConstructor method as well.
- Set metric values in the metricsValues map (using the setMetricValue method) when a setter for an individual metric is called.

Constants:
- Added TODO: do we need a METRIC_ and SORT_ version of each key?
- Created the METRIC_KEY_MAX_INTENSITY constant.

AboutFrame:
- Fixed special character in first reference: Köcher.