Persistent selection (#1086)

Persistent selection (#1086)

* Add persistsel

* Fix Makefile spacing

* Update Haiku Makefile

* Do a double pass on inversion

* Split single and double pass for easier testing

Removed lastappendpos

Eliminate suffix matches

* Check if dir is in selection before searching for files

Fix double pass

* Switch to mainline

Optimize memory moving

Handle large selection in invertsel()

Going forward with 2pass

* Update Makefiles

* Fix style

* Move forward declarations

* Remove edit selection in inversion

Replace buf with g_buf to fix CI

Fix CI

* Style changes

* Comment the code

* Style fixes

* Fix infinite loop

* Fix crash on empty invert

* Fix off-by-one-in-two-places

Off-by-twice?

* Adopt changes from master

* Only check directory if entry in it is selected

* Better organization

* Wrong variable

* Tiny optimizations

* Style fixes and updated man page

* Update man page

* Remember where we found directory path in selection

Add in progress message on invert