Import echinus-0.3.8 as wm/echinus.

Import echinus-0.3.8 as wm/echinus.
Based on PR 42188 by Alexander Polakov.

echinus is a dynamic window manager for X11 supporting managing window
s in floating, tiled and maximized layouts based on dwm. All the
configuration is made via config file in Xresources format, so it is
not necessary to recompile echinus every time you change something.

echinus supports a small subset of EWMH to be compatible with external
panels and pagers. It draws a border around windows and also an
optional title bar. The goal of development is a small, fast
window manager without features not strictly related to window
management (menus, panels, etc.)