Added dumpnodes mod

- Added dumpnodes mod, creating /dumpnodes command which can be used by admins
   to drop the nodenames and top tiles' images for every node on the server in
   the aim of beginning a process designed to generate automatically the
   colors.txt file needed by minetestmapper

mods/dumpnodes/init.lua

@@ -0,0 +1,50 @@
+local function nd_get_tiles(nd)
+    if nd.tiles then
+            return nd.tiles
+        elseif nd.tile_images then
+            return nd.tile_images
+        end
+        return nil
+end
+
+minetest.register_chatcommand("dumpnodes", {
+    params = "",
+    description = "",
+    privs = {server = true},
+    func = function(plname, param)
+        local n = 0
+        local ntbl = {}
+        for nn, nd in pairs(minetest.registered_nodes) do
+            local prefix, name = nn:match('(.*):(.*)')
+            if prefix == nil or name == nil or prefix == '' or name == '' then
+                -- nothing
+            else
+                if ntbl[prefix] == nil then
+                    ntbl[prefix] = {}
+                end
+                ntbl[prefix][name] = nd
+            end
+        end
+        local out, err = io.open('nodes.txt', 'wb')
+        if not out then
+            return minetest.chat_send_player(plname, 'io.open: ' .. err)
+        end
+        for prefix, i in pairs(ntbl) do
+            out:write('# ' .. prefix .. '\n')
+            for name, nd in pairs(i) do
+                if nd.drawtype ~= 'airlike' and nd_get_tiles(nd) ~= nil then
+                    local tl = nd_get_tiles(nd)[1]
+                    if type(tl) == 'table' then
+                        tl = tl.name
+                    end
+                    tl = (tl .. '^'):match('(.-)^')
+                    out:write(prefix .. ':' .. name .. ' ' .. tl .. '\n')
+                    n = n + 1
+                end
+            end
+            out:write('\n')
+        end
+        out:close()
+        minetest.chat_send_player(plname, n .. " nodes dumped.")
+    end,
+})