Open up support for arbitrary resource types

Introduced new extension interface ResourceRecognizer that delivers
the Resource implementation and/or sets the appropriate mime-type.

Added defaults implementation, that provides identity and content
for any type of file, and a MetaType recognizer.

Conflicts:
	org.osgi.impl.bundle.repoindex.api/src/org/osgi/service/indexer/Resource.java
	org.osgi.impl.bundle.repoindex.lib/src/org/osgi/service/indexer/impl/JarResource.java
	org.osgi.impl.bundle.repoindex.lib/src/org/osgi/service/indexer/impl/MimeType.java
	org.osgi.impl.bundle.repoindex.lib/src/org/osgi/service/indexer/impl/RepoIndex.java
	org.osgi.impl.bundle.repoindex.lib/src/org/osgi/service/indexer/impl/Util.java