Add support for Android 2.3+

There have been plenty of ppl involved in creating this version.
I don't wanna mention names as I'm sure I'd forget someone so I
just tell where help has been done:
- The partial android versions done by various ppl
- Testing on different android devices
- reviewing code (especially the in core changes)
- testing controls
- reviewing texts

A big thank you to everyone helping this to be completed!

builtin/mainmenu/init_android.lua

@@ -0,0 +1,102 @@
+--Minetest
+--Copyright (C) 2014 sapier
+--
+--This program is free software; you can redistribute it and/or modify
+--it under the terms of the GNU Lesser General Public License as published by
+--the Free Software Foundation; either version 2.1 of the License, or
+--(at your option) any later version.
+--
+--This program is distributed in the hope that it will be useful,
+--but WITHOUT ANY WARRANTY; without even the implied warranty of
+--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--GNU Lesser General Public License for more details.
+--
+--You should have received a copy of the GNU Lesser General Public License along
+--with this program; if not, write to the Free Software Foundation, Inc.,
+--51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+mt_color_grey  = "#AAAAAA"
+mt_color_blue  = "#0000DD"
+mt_color_green = "#00DD00"
+mt_color_dark_green = "#003300"
+
+--marker for android specific code
+ANDROID = true
+
+local menupath = core.get_mainmenu_path()
+local basepath = core.get_builtin_path()
+defaulttexturedir = core.get_texturepath_share() .. DIR_DELIM .. "base" ..
+					DIR_DELIM .. "pack" .. DIR_DELIM
+
+dofile(basepath .. DIR_DELIM .. "common" .. DIR_DELIM .. "async_event.lua")
+dofile(basepath .. DIR_DELIM .. "common" .. DIR_DELIM .. "filterlist.lua")
+dofile(basepath .. DIR_DELIM .. "fstk" .. DIR_DELIM .. "buttonbar.lua")
+dofile(basepath .. DIR_DELIM .. "fstk" .. DIR_DELIM .. "dialog.lua")
+dofile(basepath .. DIR_DELIM .. "fstk" .. DIR_DELIM .. "tabview.lua")
+dofile(basepath .. DIR_DELIM .. "fstk" .. DIR_DELIM .. "ui.lua")
+dofile(menupath .. DIR_DELIM .. "common.lua")
+dofile(menupath .. DIR_DELIM .. "gamemgr.lua")
+dofile(menupath .. DIR_DELIM .. "modmgr.lua")
+dofile(menupath .. DIR_DELIM .. "store.lua")
+dofile(menupath .. DIR_DELIM .. "dlg_config_world.lua")
+dofile(menupath .. DIR_DELIM .. "tab_simple_main.lua")
+dofile(menupath .. DIR_DELIM .. "tab_credits.lua")
+dofile(menupath .. DIR_DELIM .. "tab_mods.lua")
+dofile(menupath .. DIR_DELIM .. "tab_settings.lua")
+
+--------------------------------------------------------------------------------
+local function main_event_handler(tabview,event)
+	if event == "MenuQuit" then
+		core.close()
+	end
+	return true
+end
+
+local function init_globals()
+	--init gamedata
+	gamedata.worldindex = 0
+
+	local worldlist = core.get_worlds()
+
+	local found_singleplayerworld = false
+
+	for i=1,#worldlist,1 do
+		if worldlist[i].name == "singleplayerworld" then
+			found_singleplayerworld = true
+			gamedata.worldindex = i
+		end
+	end
+
+	if not found_singleplayerworld then
+		core.create_world("singleplayerworld", 1)
+
+		local worldlist = core.get_worlds()
+
+		for i=1,#worldlist,1 do
+			if worldlist[i].name == "singleplayerworld" then
+				gamedata.worldindex = i
+			end
+		end
+	end
+
+	--create main tabview
+	local tv_main = tabview_create("maintab",{x=12,y=5.2},{x=-0,y=-0})
+	tv_main:add(tab_simple_main)
+	tv_main:add(tab_mods)
+	tv_main:add(tab_settings)
+	tv_main:add(tab_credits)
+	tv_main:set_global_event_handler(main_event_handler)
+	tv_main:set_fixed_size(false)
+	ui.set_default("maintab")
+	tv_main:show()
+
+	--create modstore ui
+	modstore.init({x=12,y=6},3,2)
+
+	ui.update()
+
+	core.sound_play("main_menu", true)
+end
+
+init_globals()
+