Minor changes for MikeJ's switch_strlen_zero() and a minor refactor of BaseCDR::BaseCDR(switch_mod_cdr_newchannel_t*).  Added a sample config file, perhaps somebody can edit the makefile to copy this into the configuration when this module is enabled for build.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@4415 d0543943-73ff-0310-b7d9-9358b9ac24b2