Merge pull request #1406 from chinghanho/master

Improved statistics functions

lib/functions.zsh

 function zsh_stats() {
-  history | awk '{print $2}' | sort | uniq -c | sort -rn | head
+  history | awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | grep -v "./" | column -c3 -s " " -t | sort -nr | nl |  head -n20
 }
 
 function uninstall_oh_my_zsh() {