Rename the the meaning for shut as whats used in Eclipse.
STOP: Well stopped off above the formation. I.e. allow for flow in the
well.
SHUT: Well completely isolated from the formation. The well is removed
from the well list.
New function well_controls_clone(), implemented in terms of the
public API only, mirrors the objective of function clone_wells(),
only for well control sets. Add a basic test to demonstrate the
function too.
The 'cpty' field is for internal memory management purposes only.
No client can know of its existence, let alone inspect or directly
change the value, so it should not be used to adjudicate control set
equality. This was useful during the refactoring work to introduce
the opm-parser support, but its utility has since ceased.
Okay'ed by: [at] atgeirr and [at] joakim-hove
