Add a colorscheme command and a first zenburn them in the colors directory

colors/zenburn.kak

@@ -0,0 +1,47 @@
+# zenburn theme
+
+# first we define the zenburn colors as faces
+face zenbackground   rgb:3f3f3f
+face zentext         rgb:efefef
+face zenkeyword      rgb:f0dfaf+b
+face zenstorageClass rgb:c3bf9f+b
+face zennumber       rgb:8cd0d3
+face zencomment      rgb:7f9f7f
+face zenconstant     rgb:dca3a3+b
+face zenspecial      rgb:cfbfaf
+face zenfunction     rgb:efef8f
+face zenstatement    rgb:e3ceab
+face zenidentifier   rgb:efdcbc
+face zentype         rgb:dfdfbf
+face zenstring       rgb:cc9393
+face zenexception    rgb:c3bf9f+b
+face zenmatching     rgb:3f3f3f,rgb:8cd0d3
+
+# then we map them to code
+face value zenconstant
+face type zentype
+face identifier zenidentifier
+face string zenstring
+face error zenexception
+face keyword zenkeyword
+face operator zenfunction
+face attribute zenstatement
+face comment zencomment
+face meta zenspecial
+
+# and markup
+face title zenkeyword
+face header zenconstant
+face bold zenstorageClass
+face italic zenfunction
+face mono zennumber
+face block zenstatement
+face link zenstring
+face bullet zenidentifier
+face list zentype
+
+face Default default,rgb:3f3f3f
+face StatusLine rgb:efdcbc,rgb:2a2a2a
+face Information rgb:cc9393,rgb:2a2a2a
+face MenuBackground rgb:7f9f7f,rgb:4a4a4a
+face MenuForeground rgb:8cd0d3,rgb:4a4a4a

share/kak/colors

@@ -0,0 +1 @@
+../../colors

share/kak/kakrc

@@ -30,6 +30,23 @@ def -shell-params runtime %{ %sh{
     done
 }}
 
+def -shell-params -docstring "colorscheme <name>: enable named colorscheme" \
+    -shell-completion %{
+      prefix=${1:0:${kak_pos_in_token}}
+      (
+        for col in ${kak_runtime}/colors/*.kak; do
+            expr $(basename "${col}" .kak) : "^\(${prefix}.*\)$"
+        done
+      ) | grep -v '^$'
+    } \
+    colorscheme %{ %sh{
+        if [ $# -eq 1 ]; then
+            echo "source '${kak_runtime}/colors/$1.kak'"
+        else
+            echo -color Error 'Usage: colorscheme <scheme name>'
+        fi
+}}
+
 %sh{
     autoload() {
         dir=$1