OAK-2004 Add a way to pause the background async indexer

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1614891 13f79535-47bb-0310-9956-ffa450edef68
OAK-2011 - Log and read and write operations to different loggers

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1615417 13f79535-47bb-0310-9956-ffa450edef68
OAK-2011 - Log and read and write operations to different loggers

Fix logger name

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1615418 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'upstream-trunk' into StopwatchLogger
new constructors and javadocs
implemented Closeable interface and moved executor as class instance
varaible.