Initial PCP (Performance Co-Pilot) plugin

This plugin will collect all data relevant to PCP. Namely, it will
parse /etc/pcp.conf and then collect the following:
$PCP_SYSCONF_DIR

$PCP_VAR_DIR/config (we explicitely avoid $PCP_VAR_DIR/config/
{pmchart,pmlogconf,pmieconf,pmlogrewrite} as in 99% of the cases
they are just copies from the rpms.

$PCP_VAR_DIR/pmlogger/`hostname` (if it exists and if its size is
< 100MB by default. Unless option 'all_pcplogs' is specified)

$PCP_LOG_DIR/pmcd

$PCP_LOG_DIR/NOTICES*

$PCP_LOG_DIR/pmns

$PCP_LOG_DIR/*/*.log
$PCP_LOG_DIR/*/*.log*
$PCP_LOG_DIR/*/config*

Output of command 'pcp' to get the current status of the PCP
infrastructure.

The set of collected files has been discussed on the PCP mailing list:
http://mail.performancecopilot.org/pipermail/pcp/2014-April/004770.html