Fix bug with hierarchy editor input (issue #142)

The makeInputApplicable() method tried to access getProject() before the
init() method of the Hierarchy Editor set the input, thus it always
returned null. Now using given input to retrieve project instead.

Change-Id: Ie5267df11bfbd4281b17ac152a0271de4fd9aaf4
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>