Add guard against adding file that does not exist to GlassFishContainer's classpath.
Add an extra constructor to GlassFishContainer for usability purposes.
Add utility method GlassFishContainer.addSpecToClasspath() that can add maven style dependencies to classpath when creating GlassFish.
Remove support for recently added "embedded.glassfish.specs" system setting in as the implementation is unlikely
  to be usable.
Merge branch 'master' of https://github.com/realityforge/guiceyloops
Move to eclipselink 2.5.1.