Edited terminal print output options

[htjb]

Removed the kwarg all_output and replaced this with a new kwarg print_output which can have a value in the set [0, 1, 2]. This allows the user to print out to the terminal the full set of fits performed by maxsmooth (print_output=2), just the optimum result(print_output=1) or nothing(print_output=0).

In each case the optimum result is saved to disc and it can be useful to limit what is printed by maxsmooth in some instances to make the terminal output of other code readable. For example when wrapping maxsmooth inside other fitting algorithms (e.g. nested sampling codes like polychord).