copy stuff from vim-drvo

[justinmk]

vim-drvo supports substitutions in its :Shdo format:

https://github.com/matveyt/vim-drvo/blob/74ad4fe418c68a6a8e6876f73891c6fff831c4e0/doc/drvo.txt#L51-L60

"mask" concept seems useful:

:Selectfile [mask]					         *:Selectfile*

  Add files matching [mask] to |arglist|.

mappings?

D		Clear |arglist|
<C-D>		Show "Change drive" dialog {only available on MS-Windows}
<kMultiply>	Toggle all items in |arglist|

!		Edit shell command |:!cmd| with selected item(s)
		Hint: use double hash |c_##| to refer to |arglist|

functions:

drvo#prettify()						     *drvo#prettify()*

  This function is called by drvo |ftplugin| to prepare the buffer for
  display. It sorts the items, among other things. See |after-directory| if
  you're not happy with it.