This repo is forked from https://github.com/inkarkat/vim-mark
The difference is that this repo is the standalone version. This one does NOT depend on any other library or plugin. All you need is vim itself, nothing more!
(PS: The original one depends on a gigantic library which slows down vim, but barely uses any function of that library.)
For usage and info, refer to original repo at https://github.com/inkarkat/vim-mark