Log Message:
wm: Add yeahwm.

YeahWM is a h* window manager for X based on evilwm and aewm.

Features:

   * Sloppy Focus.
   * BeOS-like tabbed titles, which can be repositioned.
   * Support for Xinerama.
   * Simple Appearance.
   * Good keyboard control.
   * Creative usage of the mouse.
   * Respects aspect size hints.
   * Solid resize and move operations.
   * Virtual Desktops.
   * "Magic" screen edges for desktop switching.
   * Snapping to other windows and screen borders when moving windows.
   * Small binary size(ca. 23kb).
   * Little resource usage.