[Fix #54] Disable less' alternate screen

This reverts commit 34a5743789.

environment.zsh

@@ -94,7 +94,7 @@ fi
 export LESSCHARSET="UTF-8"
 export LESSHISTFILE='-'
 export LESSEDIT='vim ?lm+%lm. %f'
-export LESS='-F -g -i -M -R -S -w -z-4'
+export LESS='-F -g -i -M -R -S -w -X -z-4'
 
 if (( $+commands[lesspipe.sh] )); then
   export LESSOPEN='| /usr/bin/env lesspipe.sh %s 2>&-'