Load theme after loading all libraries

By not loading the theme at the end of lib/appearance.zsh, but rather
after loading all libraries, a theme can rely on/override not just the basic
appearance stuff like PS1.
For example the 'dieter' theme intercepts (but does not alter) the accept-line
widget to change the display on the relevant keystroke.
Features like these are impossible or subject to race conditions without
this rearrangement.

lib/appearance.zsh

@@ -33,6 +33,3 @@ ZSH_THEME_GIT_PROMPT_CLEAN=""               # Text to display if the branch is c
 
 # Setup the prompt with pretty colors
 setopt prompt_subst
-
-# Load the theme
-source "$ZSH/themes/$ZSH_THEME.zsh-theme"

oh-my-zsh.sh

@@ -7,6 +7,9 @@ fpath=($ZSH/functions $fpath)
 # TIP: Add files you don't want in git to .gitignore
 for config_file ($ZSH/lib/*.zsh) source $config_file
 
+# Load theme
+source "$ZSH/themes/$ZSH_THEME.zsh-theme"
+
 # Load all of your custom configurations from custom/
 for config_file ($ZSH/custom/*.zsh) source $config_file