Add pretty printing to swaymsg

If stdout is a tty, it will pretty print unless -r (--raw) is given.

Sample outputs:

```
~/s/s/build > ./bin/swaymsg fullscreen toggle
Error: Permission denied for fullscreen toggle via IPC

~/s/s/build > ./bin/swaymsg -t get_workspaces
Workspace 3:三
  Output: DVI-I-1
  Layout: splith

Workspace 1:一 (off-screen)
  Output: HDMI-A-1
  Layout: splith

Workspace 5:五 (focused)
  Output: HDMI-A-1
  Layout: splith

~/s/s/build > ./bin/swaymsg -t get_inputs
Input device Metadot - Das Keyboard Das Keyboard
  Type: Keyboard
  Sway ID: 9456:320:Metadot_-_Das_Keyboard_Das_Keyb

Input device Wacom Intuos S 2 Pen
  Type: Tablet tool
  Sway ID: 1386:827:Wacom_Intuos_S_2

Input device Wacom Intuos S 2 Pad
  Type: Tablet pad
  Sway ID: 1386:827:Wacom_Intuos_S_2

Input device Logitech Gaming Mouse G502
  Type: Keyboard, Mouse
  Sway ID: 1133:49277:Logitech_Gaming_Mous

~/s/s/build > ./bin/swaymsg -t get_outputs
Output DVI-I-1
  Geometry: 1920x1080 @ 3840,0
  Scale factor: 1x
  Workspace: 3:三

Output DVI-D-1
  Geometry: 1920x1080 @ 0,0
  Scale factor: 1x
  Workspace: 4:四

Output HDMI-A-1
  Geometry: 1920x1080 @ 1920,0
  Scale factor: 1x
  Workspace: 5:五
```

1 files changed, 5 insertions, 2 deletions

diff --git a/swaymsg/swaymsg.1.txt b/swaymsg/swaymsg.1.txt
index c3af28d5..1f03bee3 100644
--- a/swaymsg/swaymsg.1.txt
+++ b/swaymsg/swaymsg.1.txt
@@ -23,8 +23,8 @@ Options
 *-q, \--quiet*::
         Sends the IPC message but does not print the response from sway.
 
-*-v, \--version*::
-        Print the version (of swaymsg) and quit.
+*-r, \--raw*::
+        Use raw output even if using a tty.
 
 *-s, --socket* <path>::
         Use the specified socket path. Otherwise, swaymsg will ask sway where the
@@ -33,6 +33,9 @@ Options
 *-t, \--type* <type>::
         Specify the type of IPC message. See below.
 
+*-v, \--version*::
+        Print the version (of swaymsg) and quit.
+
 IPC Message Types
 -----------------