Shell completions through Options
- Implement shell completion generation for command line options
specified through an Options object.
- Use this support to generate the list of options for the wrapper
binary instead of hardcoding them.
- Use this support and the conversion from t_pargs/t_filenm to Options
to generate the existing completions. The only differences in the
generated completions are in the order of the options and in changing
"$n == 1" to "$n <= 1" and ".@(xtc|trr|...)" to "@(.xtc|.trr|...)".
- Extend some of the options to expose information necessary for this.
Related to #969 and #1410.
Change-Id: Ib77543367c38803ef186f6024a1af14feb806d80