Using well_controls_get_num() and well_controls_get|set_current() in WellsManager
Changed test_wellsmanager to use well_controls_get_xxx() functions.
Changes test_wells to use well_controls_get_xxx() functions.
Added new functions to set target and type and invert value of current control.
Using new function well_controls_invert_current().
Added new function well_controls_iset_distr().
Implemented well_controls_add_new() with well_controls_iset_xxx() functions.
Implemented well_control based on well_controls_iset_xxx() functions.
Implemented well_controls based on well_controls_iset_xxx() functions.
Added functions to get type, target and distr of *current* control.
Implemented well_controls based on well_controls_get_xxx() functions.
Implemented well_controls based on well_controls_get_xxx() functions.
Implemented well_controls based on well_controls_get_xxx() functions.
Implemented well_controls based on well_controls_get_xxx() functions.
Moved struct WellControls to the implementation file well_controls.c.