Import and update of hpsnmp from old psp module.

Added a new $manage_snmp option to allow for hp_mcp to completely manage
the SNMP configuration.  This assumes no other Puppet module will
interfere with managing /etc/snmp/snmpd.conf.  If $manage_snmp is set to
false, then hp_mcp assumes a separate Puppet module is managing
/etc/snmp/snmpd.conf and will call that module to make the required
changes.
Add tests for main class.

Updated tests/init.pp to be a parameterized class.
Added rspec tests for Class['hp_mcp'].
Added boolean validation to hp_mcp::hphealth.
Update reference to Management Component Pack in README.