All four view types — lines, grid, details, and grid-details — held their own colours and classify flags.
This didn’t make any sense for the grid-details view, which had to pick which one to use: the values were in there twice.
It also gave the Table in the details view access to more information than it really should have had.
Now, those two flags are returned separately from the view “mode”, which is the new term for one of those four things.
This adds an option (always on at the moment) to use a colour scale of green to yellow to orange for the file size field instead of always green. See #65.
Now when you do `--sort time` instead of saying "unknown option --sort
time" it will say "unknown options '--sort time' (choices: name...)"
with all legal options.
This also adds the legal values to the default help text.
The original options was becoming a bit unwieldy, and would have been even more so if I added the same amount of comments. So this commit splits it up.
There's no extra hiding going on here, or rearranging things within the module: (almost) everything now has to be marked 'pub' to let other sub-modules in the new options module to see it.
