If `%MAVEN_PROJECTBASEDIR%` contained whitespaces, Windows couldn't find the maven-wrapper.jar because the whitespaces were considered as argument separators.
using # in .cmd files as comment issues the following error: `Der Befehl "#" ist entweder falsch geschrieben oder konnte nicht gefunden werden.` aka command not found
The wrapper script has detected a .mvn directory, so it would be
better to assume that this is the location of the wrapper jar,
rather than the current directory (.). This change could be
enhanced by adding a separate detection loop for the jar itself
as opposed to the .mvn directory, but this is the smallest
possible change that fixes the bug.
Fixes gh-5
Michal Domagala
Andreas Ahlenstorf
Kay-Uwe Janssen
Manfred Moser
Dave Syer
Andreas Gudian