Be defensive with possibly secured APIs
Be defensive with File.listFiles()
More changes to teh way ExplodedArchive works in non-recursive mode

It is sufficient for most purposes (e.g. the ones PropertieLauncher needs)
to only read the META-INF directory (not the whole file tree). So a quick
fix is to make META-INF a special case when initializing non-recursive
entries.

Fixes gh-520