boxPointer: Rename show/hide to open/close

Pretty much like dd4709bb2, BoxPointer's show() and hide()
functions will clash with Clutter.Actor's ones.

In addition to that, on a conceptual level, the current API
is not great, because calling boxPointer.hide() won't result
in boxPointer.actor.visible == false.

For these reasons, rename show() and hide() to open() and
close(). A compatibility layer will be added in a following
commit, warning about the usage of show() and hide().

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/153

js/ui/workspaceThumbnail.js

@@ -1142,8 +1142,6 @@ var ThumbnailsBox = new Lang.Class({
         let workspaceManager = global.workspace_manager;
         let themeNode = this.get_theme_node();
 
-        forWidth = themeNode.adjust_for_width(forWidth);
-
         let spacing = themeNode.get_length('spacing');
         let nWorkspaces = workspaceManager.n_workspaces;
         let totalSpacing = (nWorkspaces - 1) * spacing;