Moved WellInjectionproperties to separate files.
Added CMODE_UNDEFINED enum values
Fixed initialisation of well properties

Previously the control mode was initialized to ORAT; this was later set
to the correct value when parsing the relevant keywords - but in the
case of a SHUT well the control mode was not updated, and we were left
with a well under ORAT control.
Fixed log message
Added extra test case for closing wells.
Merge pull request #326 from joakim-hove/wellsmanager-crash

Wellsmanager crash