This is an important refactor of the way documentation generation works

* Installs luarocks WITH it's executable (easy to install other rocks if necessary)
* Use Lua supplied with luarocks
* Create Utils/luadocumentor.bat, which works with RELATIVE PATH ! -> Everybody can generate the doc
* Updated launch files accordingly

Utils/luarocks/systree/share/lua/5.1/pl/MultiMap.lua

@@ -0,0 +1,65 @@
+--- MultiMap, a Map which has multiple values per key. <br>
+-- @class module
+-- @name pl.MultiMap
+
+--[[
+module ('pl.MultiMap')
+]]
+
+local classes = require 'pl.class'
+local tablex = require 'pl.tablex'
+local utils = require 'pl.utils'
+local List = require 'pl.List'
+
+local index_by,tsort,concat = tablex.index_by,table.sort,table.concat
+local append,extend,slice = List.append,List.extend,List.slice
+local append = table.insert
+local is_type = utils.is_type
+
+local class = require 'pl.class'
+local Map = require 'pl.Map'
+
+-- MultiMap is a standard MT
+local MultiMap = utils.stdmt.MultiMap
+
+class(Map,nil,MultiMap)
+MultiMap._name = 'MultiMap'
+
+function MultiMap:_init (t)
+    if not t then return end
+    self:update(t)
+end
+
+--- update a MultiMap using a table.
+-- @param t either a Multimap or a map-like table.
+-- @return the map
+function MultiMap:update (t)
+    utils.assert_arg(1,t,'table')
+    if Map:class_of(t) then
+        for k,v in pairs(t) do
+            self[k] = List()
+            self[k]:append(v)
+        end
+    else
+        for k,v in pairs(t) do
+            self[k] = List(v)
+        end
+    end
+end
+
+--- add a new value to a key.  Setting a nil value removes the key.
+-- @param key the key
+-- @param val the value
+-- @return the map
+function MultiMap:set (key,val)
+    if val == nil then
+        self[key] = nil
+    else
+        if not self[key] then
+            self[key] = List()
+        end
+        self[key]:append(val)
+    end
+end
+
+return MultiMap