Add 0.5.0-M1 javadocs

This commit deliberately avoids updating the /javadoc/current/
directory to mirror 0.5.0-M1.  That should probably stay at 0.4.4
until 0.5.0 reaches final release.  This also doesn't update the
wikidoc (now asciidoc, kind of an anachronism) directory for 0.5.0-M1,
since we're pushing those changes to S3 now.  Does not update the
titan.thinkaurelius.com index either.