NUTCH-1360 fix entity in configuration

git-svn-id: https://svn.apache.org/repos/asf/nutch/trunk@1554791 13f79535-47bb-0310-9956-ffa450edef68
NUTCH-1080 Type safe members, arguments for better readability

git-svn-id: https://svn.apache.org/repos/asf/nutch/trunk@1554881 13f79535-47bb-0310-9956-ffa450edef68
NUTCH-1670 set same crawldb directory in mergedb parameter

git-svn-id: https://svn.apache.org/repos/asf/nutch/trunk@1554883 13f79535-47bb-0310-9956-ffa450edef68