add plugin:percol (#4582)

plugins/percol/README.md

+## percol
+
+Provides some useful function to make [percol](https://github.com/mooz/percol) work with zsh history and [jump plugin](https://github.com/robbyrussell/oh-my-zsh/blob/master/plugins/jump/jump.plugin.zsh)
+
+### Preview
+![Preview](http://t1.qpic.cn/mblogpic/eb1c8f9d2b9f62d19fa8/2000.jpg)
+
+### Requirements
+
+```shell
+pip install percol
+```
+
+And [jump](https://github.com/robbyrussell/oh-my-zsh/blob/master/plugins/jump/jump.plugin.zsh) for `oh-my-zsh` is a optional requirement.
+
+### Usage
+
+For default
+
+- `^-r` bind to `percol_select_history`.You can use it to grep your history with percol.
+
+- `^-b` bind to `percol_select_marks`.You can use it to grep your bookmarks with percol.
+

plugins/percol/percol.plugin.zsh

+if which percol &> /dev/null; then
+    function percol_select_history() {
+        local tac
+        which gtac &> /dev/null && tac="gtac" || { which tac &> /dev/null && tac="tac" || { tac="tail -r" } }
+        BUFFER=$(fc -l -n 1 | eval $tac | percol --query "$LBUFFER")
+        CURSOR=$#BUFFER
+        zle -R -c
+    }
+
+    zle -N percol_select_history
+    bindkey '^R' percol_select_history
+
+    if which marks &> /dev/null; then
+        function percol_select_marks() {
+            BUFFER=$(marks | percol --query "$LBUFFER" | awk '{print $3}')
+            CURSOR=$#BUFFER # move cursor
+            zle -R -c       # refresh
+        }
+        zle -N percol_select_marks
+        bindkey '^B' percol_select_marks
+    fi
+fi