skytools.skylog: initial implementation of UdpTNetStringsHandler
skytools.skylog: moved hostaddr resolving to module init

No need to do it per log call as hostname is constant currently.
skytools.skylog: added more fields to UdpTNetStringsHandler log message
set_tcp_keepalive: accept socket object directly
Add consumer_filter option to simple_local_consumer.
pgq.logutriga: don't quote '-'

Not needed and now logutriga() behavior matches
skytools.db_urlencode() and urllib.quote_plus().
pgq.Consumer: non-lazy loading should use RetriableEvent
pgq: move RetriableEvent to consumer.py

It's hard to get overview if the retry-related code
is laying around in different places.

As only Consumer class deals with retry, move all crap
into same file.
Merge remote-tracking branch 'petr/master'
walmgr: new command createslave and new option --synch-standby
Merge remote-tracking branch 'tarvip/walmgr-createslave'
Merge branch 'feature/skylog_tnetstrings_via_udp' into develop
Merge branch 'master' of https://github.com/markokr/skytools into develop