PMD Warnings fixed.
(from 124 to 86)
Merge pull request #893 from Catrobat/PMDWarnings

PMDWarnings removed. Part 1 - Part 4
fixed PMDWarnings.
fixed PMDWarnings.
Merge pull request #899 from Catrobat/PMDWarningsPart7

removed PMDWarnings Part7
Merge pull request #900 from Catrobat/PMDWarningsPart6

removed PMDWarnings Part6
SourceTest for printStackTrace
changed printStackTrace calls to Log calls
changed all 30 printStackTrace calls in package catroid to use the logger instead
Exception variable names are full Exception names
Merge pull request #918 from Catrobat/noPrintStackTrace

new SourceTest that forbids printStackTrace()