Added per-listener ruleset and inputname support to imrelp.

Despite remaining comments to the contrary in the imrelp.c file, the relp library has been updated to allow us to support per-instance rulesets and other parameters for some time now.  As such, this patch modifies the imrelp.c file to utilize that functionality in order to define rulesets and input names on a per-listener basis.

The code changes are based on the existing ruleset and input name handling in other input modules (namely imptcp).  Support for these configuration options was also added to the old format configuration structure.  It appears to work in my (admittedly limited) testing of the patch on RHEL6.