NUTCH-1837 Upgrade to Tika 1.6 (jnioche)

git-svn-id: https://svn.apache.org/repos/asf/nutch/trunk@1623562 13f79535-47bb-0310-9956-ffa450edef68
NUTCH-1840

git-svn-id: https://svn.apache.org/repos/asf/nutch/trunk@1624471 13f79535-47bb-0310-9956-ffa450edef68