Examples: Parsing sets/flags and enums about cligen

[c-blake]

Hey, Mamy. Thanks. Glad you like it. Your code looks good. I should probably have some example code for doing enums.

[c-blake]

Hey. So, I added generic support for any enums. See test/Enums.nim. I have also changed things in a few backward incompatible ways for people defining their own argParse/argHelp like you (see RELEASE_NOTES.md) and added support for seq[T] for almost all the regular T supported by argcvt. I ran into some trouble supporting seq[enum], though...Internal compiler error. Similar generic support for set[T] is probably not so bad, but not as widely applicable since T is more restricted. The internal error has me regretting a bit using templates instead of generic functions, but then the way I let CLI authors pick both the value and type of seqDelimit has me not regretting.

[c-blake]

Ok. Both any enums and any sets of enums should just work by default now. You should be able to just comment out/delete your definitions. There is also a new "+="/"-=" syntax for updating existing values as in --licenses+=MIT. So, I am closing this issue.

I don't know if you have any other user-defined argParse and argHelp, but there have been major changes in how they work. See RELEASE_NOTES.md or argcvt.nim or DETAILS.md. I will soon tag some new release version to cover that backward incompatibility.