Fix the timestamps set by the collectd plugin

Timestamps should be in microseconds instead of milliseconds.

Fix #1075. Close #1076
Use FINE instead of TRACE when fine logging

It turns out TRACE is a higher logging level than DEBUG which doesn't
make much sense and is confusing. We can use FINE to achieve the same
thing and it's descriptive and less confusing
Remove some nonsense
Make the raft logging configurable
Set the node's connection string when creating a new raft server
Update the changelog for #1085
Don't try to take 2 snapshots at a time

Fix #943. Close #1081
Rename some constants

(from_clause.go,query.yacc,query_types.h): FROM_INNER_JOIN -> FROM_JOIN
Support joining multiple series using regex or list