comm_connection: close idle tcp connections

check for idle connections occasionally

a tcp connection is considered to be idle if no data has been sent for some time

scalaris.cfg
  tcp_idle_timeout: time after the connection is considered to be idle

git-svn-id: https://scalaris.googlecode.com/svn/trunk@5908 71766da9-9752-0410-ab17-bfafa751c56a
remove debug output

git-svn-id: https://scalaris.googlecode.com/svn/trunk@5909 71766da9-9752-0410-ab17-bfafa751c56a
comm_connection: check for idle connection more often

git-svn-id: https://scalaris.googlecode.com/svn/trunk@5910 71766da9-9752-0410-ab17-bfafa751c56a
avoid erlang:now() use os:timestamp() when possible


git-svn-id: https://scalaris.googlecode.com/svn/trunk@5911 71766da9-9752-0410-ab17-bfafa751c56a
gossip: add a lot more specs plus some cleanup

git-svn-id: https://scalaris.googlecode.com/svn/trunk@5912 71766da9-9752-0410-ab17-bfafa751c56a
gossip: add specs for gossip2 to webhelpers (commeted out)

git-svn-id: https://scalaris.googlecode.com/svn/trunk@5913 71766da9-9752-0410-ab17-bfafa751c56a
gossip: uncomment gossip2 in sup_dht_node and dht_node_join
gossip: activate gossip2 instead of gossip1 in webhelpers