References:
1. http://man7.org/linux/man-pages/man2/posix_fadvise.2.html
2. https://www.oreilly.com/library/view/linux-system-programming/9781449341527/ch04.html

Remove extra static string.

This reverts commit 407b690404.

- press pick plugin key
- navigate away from the plugin directory (to ~, say)
- try to open any file, fails

When we are in run plugin mode, but detect we are in a different
context or a non-plugin directory, just cancel the runplgin mode
and continue as usual.

It also cleans up the plugin run function.

* Implement plugins control of nnn + plugins

* Refactor plugins control code and fix getplugs to recognize hidden files

* Fix bug when going to dir on non-current context from plugin

* Fix some plugins to work on openbsd and freebsd

* Renamings

* Switch to -R flag in cp instead of -r; BSDs complain

* Change braces of function location

* Rewrite plugin creation in README and add new plugins to the table

* Update the fzcd script to include fzy or fzf

* Change plugin name resolve-link-dir -> lncd

* Fixing plugins README table

* Remove some cd plugins but add them as examples to plugins README