Sort by FIBER; set sciencemask et al by name or number even for SV

[sbailey]

This PR adds a few features used by the Survey Validation Data Challenge:

• sort output by FIBER (even though downstream code shouldn't care about the fiber order, it currently does care)
• allow setting sciencemask etc. by name in addition to number, including for SV target catalogs
• There were also some updates to how it parses fiberassign options into fba_run and fba_merge_results options, which might make that slightly more maintainable by making it opt-in instead of opt-out.

[tskisner]

This looks good, thanks!