Character Categories and Collation-aware Sorting

[ripta]

1. New uni sort that sorts input. The flag -lsorts using a language-specific collation. Collations are from golang.org/x/text/collate and compiled in.
2. New uni sort list that lists all the language-specific collations compiled in.
3. Expanded uni list with new default option -o categories that shows the character category.
4. Expanded uni list with new --categories (-C) to select list by character category.
5. Add uni cat that shows an aggregate report of unicode character categories.