Add spec for flux rename/drop function (#462)
Add spec for flux rename/drop function (#462)

* Add initial rename specification to SPEC.md

* Tweak language in spec to be more explicit

* Update spec to be in accordance with final design decisions


influxdb/influxdb,influxdb/influxdb,nooproblem/influxdb,nooproblem/influxdb,nooproblem/influxdb,li-ang/influxdb,influxdb/influxdb,influxdata/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,influxdb/influxdb,li-ang/influxdb,nooproblem/influxdb,mark-rushakoff/influxdb,mark-rushakoff/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,influxdata/influxdb,influxdb/influxdb,mark-rushakoff/influxdb