* 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

* Initial commit of sessions implementation

* Reduce code duplication

* Move load session to program flag -e

* Fix context initialization problem when loading session

* Add pinned directory to session and reduce session file size

* Make load_session print an error if exists and few minor adjustments

* Refactor session's file structure

* Initialize required structures in load_session before loading

* Add load session dynamically, restore last session, and extra fixes

* Fix indentation

* Add sessions documentation to man page

* Update fish completions with sessions and make some improvements

* Move to single keybinding session management and add help info

* ESC when asked to insert session name behaves better

* Add sessions completion for bash

* Remove pinned dir from session and minor code refactors

* Define _XOPEN_SOURCE_EXTENDED on SmartOS

Enables wide ncurses.

* SmartOS has alloca() in alloca.h

* SmartOS does not have sig_t

* dprintf() is not available on SmartOS

So replace its usage with fprintf.

* SmartOS has no d_type

* SmartOS has no CLOCK_MONOTONIC_RAW

* SmartOS has no O_DIRECTORY

* Work around SmartOS not having mime detection

* Missing comma

If the formatted string is longer than 17 characters the string won't
be null terminated, causing gibberish to be printed on the status line
and possibly worse.

This occurs with my current locale in which a date is printed as such:

  2019-okt.-15 19:26

Which is 18 characters.

* Added copy/move-as (copy/move and rename)

* Little refactorings

* Also handle selection file for cpmv_rename()

This patch changes the mouseinterval to 0. And handles detection of
doubleclicking events internally.

This allows much faster response times for mouse clicks as nnn no longer
has to wait for ncurses to confirm what type of click it was.

It introduces a new config setting for changing how many milliseconds it
may take for a double click to be registered.

* unmount() ask for target if not found

unmount() now properly asks for which target to unmount if it cannot
automatically deduce which folder to unmount.

* no more automatic unmounts outside of cfgdir

KDE dragon player collides with the name of the drag/drop dependency. On
archlinux the binary is renamed to `dragon-drag-and-drop`.

This change tries `dragon-drag-and-drop` before defaulting to `dragon`.

* Added 2 plugins for drag and drop support

These scripts uses https://github.com/mwh/dragon
and curl.

It allows nnn to drag and drop files either to other programs, or to
itself.

* added link to dependency and spelling

* added drag/drop-file scripts to readme table