Reporting: occasionally reap child threads

I noticed that, at least on Python 2.4, memory for threads doesn't
get freed until the threads are joined.  This patch causes the
collector to periodically go through and reap those threads.

Tested in production for ~1 month, no reported issues.
Merge pull request #152 from fennm/reporting-collector-reap-children

Reporting: occasionally reap child threads
FAM: Get full traceback when event handling errors
POSIX: Properly stringify ACLs with no user/group specified

This is just a workaround to avoid a traceback; the real fix will
involve making the POSIX tool properly handle ACLs with no user/group
given, which refer to the current user/group of the file they apply
to.
Don't parse unicode XML with encoding

Fix another place where a unicode XML string with an encoding
declaration may be read.  Cf. 0f8d403d1a86cfbfe8222662dc445e16e8f7eff9
added missing docstring
misc/bcfg2.spec: Fix BuildRequires for RHEL7

Signed-off-by: Sol Jerome <sol.jerome@gmail.com>
doc: added multiprocessing core docs, including tmpwatch fix
misc/bcfg2.spec: Fix bcfg2-web Requires for EPEL7

Signed-off-by: Sol Jerome <sol.jerome@gmail.com>
misc/bcfg2.spec: Pull in cherrypy toggle from epel

This allows one to disable building of the bcfg2-server-cherrypy
package.

Signed-off-by: Sol Jerome <sol.jerome@gmail.com>
misc/bcfg2.spec: Merge changelog from epel

Signed-off-by: Sol Jerome <sol.jerome@gmail.com>