Support 'vertical' Workspace warping

'Vertical' Workspace warping is a variant of the existing Workspace
warping feature: When a user drags a window to the edge of the Screen,
the window is warped to the next / previous workspace.

'Vertical' Workspace warping detects a drag towards the upper / lower
border of the screen and warps the current workspace about an 'offset'.
Example given, lets say the user has 9 workspaces and considers them to
form a 3x3 grid:

  +-+-+-+
  |1|2|3|
  +-+-+-+
  |4|5|6|
  +-+-+-+
  |7|8|9|
  +-+-+-+

An 'offset' of 3 warps from workspaces 2 to workspace 5 (or 8), when a
window is dragged to the bottom / top border.

New configuration ressources:

    session.screenN.workspacewarpingvertical: true
    session.screenN.workspacewarpingverticaloffset: X

1 files changed, 3 insertions, 1 deletions

diff --git a/src/ScreenResource.hh b/src/ScreenResource.hh
index 7f1e621..bc782e1 100644
--- a/src/ScreenResource.hh
+++ b/src/ScreenResource.hh
@@ -37,6 +37,7 @@ struct ScreenResource {
        max_disable_move,
        max_disable_resize,
        workspace_warping,
+       workspace_warping_vertical,
        show_window_pos,
        auto_raise,
        click_raises;
@@ -53,7 +54,8 @@ struct ScreenResource {
         menu_alpha,
         menu_delay,
         tab_width,
-        tooltip_delay;
+        tooltip_delay,
+       workspace_warping_vertical_offset;
     FbTk::Resource<bool> allow_remote_actions;
     FbTk::Resource<bool> clientmenu_use_pixmap;
     FbTk::Resource<bool> tabs_use_pixmap;