Add dircycle plugin: enables cycling through the directory stack

plugins/dircycle/dircycle.plugin.zsh

+##
+# dircycle plugin: enables cycling through the directory
+# stack using Ctrl+Shift+Left/Right
+
+eval "insert-cycledleft () { zle push-line; LBUFFER='pushd -q +1'; zle accept-line }"
+zle -N insert-cycledleft
+bindkey "\e[1;6D" insert-cycledleft
+eval "insert-cycledright () { zle push-line; LBUFFER='pushd -q -0'; zle accept-line }"
+zle -N insert-cycledright
+bindkey "\e[1;6C" insert-cycledright