2nd try at not adding (so not messing with locks of) unparsed stuff to Exec env
apparently isRawData has to hang off DKV.get()

      if( val.isFrame() ) {
        val = DKV.get(k);       // Fetch the whole thing
        if( val == null ) continue; // Racing delete got it?
->      if( val.isRawData() ) continue; // don't add unparsed stuff

this passes build.sh junit/R tests plus my test
Merge branch 'master' of github.com:0xdata/h2o