gossip_cyclon: remove superfluous is_state type_checker

Fixes failing typecheck tests

git-svn-id: https://scalaris.googlecode.com/svn/trunk@6990 71766da9-9752-0410-ab17-bfafa751c56a
memtest_SUITE: fix printing of error messages

git-svn-id: https://scalaris.googlecode.com/svn/trunk@6991 71766da9-9752-0410-ab17-bfafa751c56a
gossip: fix bug in select_data() callback

When returning retry on a select_data() call the trigger message was stored in
the message queue. When contiously returing 'retry' (e.g. in a one node setup with
gossip_cyclon), this led to a self-accelarting endless recursion of resending
and storing the trigger message. Now refactored to ignore the given trigger, i.e.
the current trigger is discarded an the select_data() is called again on the next
again. The return of the select_data() is changed to 'discard_msg' (instead of
'retry') accordingly.

This also fixes the failures in memtest_SUITE.

git-svn-id: https://scalaris.googlecode.com/svn/trunk@6992 71766da9-9752-0410-ab17-bfafa751c56a
rbr: optimise and fix some types

git-svn-id: https://scalaris.googlecode.com/svn/trunk@6993 71766da9-9752-0410-ab17-bfafa751c56a
rbr: minor performance optimisations

git-svn-id: https://scalaris.googlecode.com/svn/trunk@6994 71766da9-9752-0410-ab17-bfafa751c56a
rbr: fix kv_on_cseq:max/2 type spec (regression of r6933)

note: cannot use is_subtype/2 notation in the two alternatives due to tester limitations

git-svn-id: https://scalaris.googlecode.com/svn/trunk@6995 71766da9-9752-0410-ab17-bfafa751c56a
gossip_cyclon: refactor cycle counting
gossip_cyclon: cleanup type specs
gossip_cyclon: performance tweak for startup

Avoids a 'discard_msg' in the select_data() of the first node, thereby
providing a faster startup of gossip_cyclon.
gossip: add test group for all gossip tests