xsession: split from bspwm, update README.md and check_dependencies.sh

xsession/.xsession

@@ -0,0 +1,36 @@
+#!/bin/sh
+
+if [ -z "$EDITOR" ]; then
+    . ~/.profile
+fi
+
+xrandr --auto
+xrandr --output HDMI1 --right-of DP1
+xsetroot -solid '#94a3b8'
+xrdb -merge ~/.Xresources
+setxkbmap pl -option ctrl:nocaps
+xmodmap ~/.xmodmaprc
+
+# lock screen on suspend/hibernate
+if which xss-lock slock >/dev/null; then
+    xss-lock slock &
+else
+    ( echo "Missing command(s):"; which xss-lock slock 2>&1 ) | xmessage -file -
+fi
+
+# run emacs daemon if not running
+emacsclient --eval nil -a '' &
+
+xsettingsd &
+
+exec qtile start
+
+if which bspwm > /dev/null; then
+    sxhkd &
+    xsetroot -cursor_name left_ptr
+    exec bspwm
+fi
+exec /usr/bin/i3
+dwm-clock &
+exec /usr/local/bin/dwm
+exec xterm