tmx parser and tileset example

tmxparser (https://github.com/andrewrk/tmxparser) into libs for loading
tilemaps, also added an example
added al_draw and tilemap/tileset classes

added classes:
* tile
* tileset
* tilemap
tilemap/tileset changes

small changes
tileset parser

added method to load a tileset from a tmx file, also added new function
(slice_bitmap) in al_draw
Merge branch 'Development' of https://github.com/demiurgosoft/dont-crush-my-castle into Maps
Update tilemap

Updated:
* tileset.h
* tilemap.h
Erased:
* debug_log.h
* al_draw.h
* tmxparser
update maps v0.2

* code divided into .h and .cpp
* tiles code now in tile.h/tile.cpp
* map code now into lib/map
Updated tilemap and tileset

Updated some methods of tileset and tilemap, created constructor for
tileset (still to review)
minor changes
Updated maps

* bugs fixed
* const methods
* removed destroyer form tile
Merge pull request #4 from demiurgosoft/Maps

Maps