Removes the wlroots dependency from the common code. To remove the
dependency on the header, the defines and log-level enum are copied
over.
This causes a redefine error if both the wlr and the sway log.h are
included.
This starts up the event loop and wayland display and shims out the
basic top level rendering concepts. Also includes some changes to
incorporate pango into the 1.x codebase properly.
