display clients count in monocle symbol

- Replicate missing functionality from dwl to display the client count in monocle mode
  - Add ltsymbol field to Monitor struct
  - Display client count in monocle mode when greater than zero
- Tested with somebar and dwlb

Remove rootcolor

Missing apostrophe

add missing comma in "MonitorRule"

add a missing comma for the example

Fix spacing and replace it with tabs

fix spelling

Fixed 'unused variable' compiler warning.

Add appid field to printstatus() output

Adds an appid field to printstatus which can be used to monitor the
currently active application.

implement repeatable keybindings

allow configure x and y of outputs

use sigaction(2) for signal handling

References: http://git.suckless.org/dwm/commit/712d6639ff8e863560328131bbb92b248dc9cde7.html

bump version to 0.4

remove `--long` from git-describe command

return early if selmon is not part of the output layout in dirtomon()

instead of checking twice

simplify check in urgent()

we only care if it returned a client or not

arrange monitor after updating fullscreen background and lock surfaces

also update locked_bg node position in updatemons()

add blank lines to make updatemons() more readable

update comment about client_set_size() as no-op

check if a client is resizing before checking if it's visible

It's not like it's noticeable, but theoretically this is faster