MAHOUT-1217: Nearest neighbor searchers sometimes fail to remove points

This fixes FastProjectionSearch's searchFirst() which was not also searching
through pendingAdditions. I think I replicated the bug in the new testRemove()
in SearchSanityTest that now passes.



git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1483776 13f79535-47bb-0310-9956-ffa450edef68