Rev 7831 merged from trunk.

git-svn-id: http://svn.terracotta.org/svn/ehcache@7832 b9324663-ca0f-0410-8574-be9b3887307d
CRQ-50 ENG-88 Modified cache manager shutdown to be more insistent wrt statistics pool shutdown. Added test for system property override of per CM statistics pool size. 

git-svn-id: http://svn.terracotta.org/svn/ehcache@7833 b9324663-ca0f-0410-8574-be9b3887307d