Replace deprected property

When executing the launch script under Mac OS X 10.9 there is a
deprecation warning:

~~~
com.apple.macos.useScreenMenuBar has been deprecated. Please switch to
apple.laf.useScreenMenuBar
~~~
Merge pull request #39 from choffmeister/apple-deprecated

Replace deprecated Mac OS specific property
Fixes #42
0.5.2 release
Merge branch 'develop' of github.com:xerial/sbt-pack into develop
update test scripts
Upgraded to sbt-pack-0.5.2
#41 On packResourceDir setting