bot: implemented asynchronous pathfinding

nav: floyd-warshall matrices and practice updates are done asynchronously by now
add: yb_threadpool_workers cvar, that controls number of worker threads bot will use
add: cv_autovacate_keep_slots, the amount of slots to keep by auto vacate
aim: enemy prediction is now done asynchronously by now
bot: minor fixes and refactoring, including analyze suspend mistake (ref #441)

note: the master builds are now NOT production ready, please test before installing on real servers!

src/graph.cpp

@@ -1196,6 +1196,7 @@ void BotGraph::showFileInfo () {
    msg ("  compressed_size: %dkB", m_graphHeader.compressed / 1024);
    msg ("  uncompressed_size: %dkB", m_graphHeader.uncompressed / 1024);
    msg ("  options: %d", m_graphHeader.options); // display as string ?
+   msg ("  analyzed: %s", (m_graphHeader.options & StorageOption::Analyzed) ? "yes" : "no"); // display as string ?
 
    msg ("");