IGMPv3: removed unused methods
IGMPv3: fixed report sending

- reports are now sent to ALL_IGMPV3_ROUTERS_MCAST
- empty ALLOW/BLOCK records are omitted
- ALLOW/BLOCK records are sent in one report
IGMPv3: set category of test log messages
IGMPv3 tests: use %postrun-command
IGMP: update fingerprint test

Fingerprints are changed after 'IGMPv3: fixed report sending'
IGMPv3: fix stages of initialization
IGMPv3: add router tests