editors/mle: import mle-1.7.2

Packaged by Kevin Bloom for wip.

mle is a small, flexible, terminal-based text editor written in C.
Its features include:

* Full UTF-8 support
* Syntax highlighting
* Stackable key maps (modes)
* Extensible via Lua
* Scriptable rc file
* Key macros
* Multiple splittable windows
* Regex search and replace
* Large file support
* Incremental search
* Linear undo and redo
* Multiple cursors
* Auto indent
* Headless mode
* Navigation via ctags
* Movement via less
* Fuzzy file search via fzf
* File browsing via tree
* File grep via grep
* String manip via perl

(wiz)