make OsgiLargeTest runnable on linux system

fix problem with excetuable permision by running sh shell instead of
file (problem caused by bug in maven
http://jira.codehaus.org/browse/MRESOURCES-132)
Fix property setting in gradle plugin

Use method calls instead of property shortcut as it does not work
properly  with overloading setters.
Merge pull request #581 from pwielgolaski/master

fix gradle plugin - issue #574