STANBOL-1128: The FST models are now updated after changes to the SolrIndex. The long indexVersion as reported by the DirectoryReader of the SolrIndex is now used as version indicator (for both FST models and the EntiyCache); Threads of the ThreadPool are now created with the lowest priority; Improved loggings and the README

git-svn-id: https://svn.apache.org/repos/asf/stanbol/trunk@1517757 13f79535-47bb-0310-9956-ffa450edef68