Remove duplicate keybindings from i3 config

Removed the keybindings now handled by sxhkd. Some are changed around
slightly, most of them are still the same.

.config/i3/config

@@ -31,19 +31,9 @@ font $font
 # Use Mouse+$mod to drag floating windows to their wanted position
 floating_modifier $mod
 
-# start a terminal
-bindsym $mod+Return exec alacritty #i3-sensible-terminal
-
 # kill focused window
 bindsym $mod+Shift+x kill
 
-# start dmenu (a program launcher)
-#bindsym $mod+space exec dmenu_run
-# There also is the (new) i3-dmenu-desktop which only displays applications
-# shipping a .desktop file. It is a wrapper around dmenu, so you need that
-# installed.
-bindsym $mod+space exec --no-startup-id i3-dmenu-desktop
-
 # change focus
 bindsym $mod+h focus left
 bindsym $mod+j focus down
@@ -184,26 +174,10 @@ bar {
   status_command i3status
 }
 
-# I3 System commands: restart, reload, shutdown, lock
 # reload the configuration file
 bindsym $mod+Shift+y reload
 # restart i3 inplace (preserves your layout/session, can be used to upgrade i3)
 bindsym $mod+Shift+r restart
-# exit i3 (logs you out of your X session)
-bindsym $mod+Shift+s exec --no-startup-id `[ $(printf "NO\nYES" | dmenu \
-    -nb "#222222" -sb "#aa0088" -sf "#ffffff" -fn Monospace-11 \
-    -nf "#7777bb" -i -p "Exit i3 X session?") = "YES" ] && i3-msg exit`
-# lock i3 screen
-bindsym $mod+Shift+p exec i3lock
-
-# enable function (/media) key functionality
-# TODO: set up next song, previous song, pause, etc
-# see: https://www.reddit.com/r/i3wm/comments/3a6nh3/help_how_to_use_function_keys_in_i3_config/
-bindsym XF86MonBrightnessUp exec `xbacklight -inc 10`
-bindsym XF86MonBrightnessDown exec `xbacklight -dec 10`
-bindsym XF86AudioMute exec `pulsemixer --toggle-mute`
-bindsym XF86AudioRaiseVolume exec `pulsemixer --change-volume +5`
-bindsym XF86AudioLowerVolume exec `pulsemixer --change-volume -5`
 
 # set a pretty wallpaper
 exec_always --no-startup-id feh --bg-scale ~/Pictures/wall.jpg