SLING-3957 - Support m2e 1.6 or newer

Use Require-Bundle instead of Import-Package for stuff provided by m2e .
This works around that org.apache.maven, org.codehaus and other packages
are exported with mandatory provider=m2e attribute.

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1626215 13f79535-47bb-0310-9956-ffa450edef68