Created fully implicit simulator sim_fibo_ad.
Merge remote-tracking branch 'atgeirr/fully-implicit' into fully-implicit
Include well support in FIBOSolver interface.

Update callers accordingly.
Added Span.
Use Span.
Merge remote-tracking branch 'atgeirr/fully-implicit' into fully-implicit
Add gather/scatter support for wells
Add an operator<< for outputting vector results.

Use it out print reservoir and well pressures at end of solution.