OSGi headers added to core, java and junit.

This uses the maven felix bundle plugin.
RuntimeOptions can be instantiated in OSGi containers

RuntimeOptions loads the USAGE.txt on class initialization. However 
gherkin.util.FixJava is in the gherkin jar/bundle and in an OSGi 
container the class loader of FixJava does not see the text file, 
because it is located in the core jar/bundle.

Printing the usage text in an OSGi container is not needed, so the code
has been changed to lazy load the resource.