PIM: add statistical tests
PIMSM: turn off CISCO_SPEC_SIM mode
PIMSM: added parameters for timer periods specified in the RFC
PIM: organized includes, added INET_API declarations
PIMSM: removed Cisco specific info() method
PIMSM: deleted some useless flags and fields
PIMSM: less code duplication
PIMSM: simplifying signal handling code (and fixing a memory leak)