refactor all history modifications into discrete plugins

lib/history.bash

@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-
-# Bash History Handling
-
-shopt -s histappend                                      # append to bash_history if Terminal.app quits
-export HISTCONTROL=${HISTCONTROL:-ignorespace:erasedups} # erase duplicates; alternative option: export HISTCONTROL=ignoredups
-export HISTSIZE=${HISTSIZE:-5000}                        # resize history size
-export AUTOFEATURE=${AUTOFEATURE:-true autotest}         # Cucumber / Autotest integration
-
-function rh {
-  history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
-}