[env] Stack lib: fix pdeln return status, add pdisp, pdeclare, pset,
rename add into padd for consistency
[env] CD: use OLDPWD system variable, use the user define 'cd' fct and
not the builtin one
[git] Add fct git-ci
[vim] Don't use hasmapto() but mapcheck() instead, which is not the
same...
[vim] Replace undo :u by undo and :re by redo, to work in select/visual mode
[vim] Allow to scroll in visual/select mode + first attempt to support
MRUs with tlib_vim