mix number should be output as ordinal number fix #552
don't mix when no update observed, fix #181
works good in case that version is more than 100th
cpplint ok
avoid infinite loop in `get_model` fix #711
add test
Merge pull request #708 from jubatus/feature/dont_mix_without_update

don't mix when no update observed, fix #181
Merge pull request #705 from jubatus/feature/ordinal_mix_counting

ordinal mix counting
avoid unneeded double check
exclude `update_members()` because retrying node choice is invoked by selecting oneself
Merge pull request #715 from jubatus/debug/avoid_infinite_loop_in_get_model

avoid infinite loop in `get_model` fix #711