Building base material undump script.

Based on an idea in https://github.com/peterix/dfhack/issues/119
Better way to check for the contained_items field.
Ignore Mac OS X .DS_Store files
New plugin: building-hacks. Allows workshops to block liquids and consume mechanical power, connect to machines.
Added animation and on update callback.
building-hacks: added lua convenience function, made impassible tile fix optional.
eventful: added support for custom workshops and a convenience function to interpose side panel generation
docs: updated eventful lua api and added building-hacks docs.
Added building filter to advfort.
Added rendermax plugin- a bunch of rendering hax in one. Small fix to skeleton.
rendermax: removed all the opengl and sdl stuff. Now it work with magic alone.
Forgot to add the plugin itself. Also some improvements
Added help for truecolor light testing thing. Also added colors.
Implemented lua interface.
Added light script. Can be ran with "static" to recalculate only on '~' press.
Fixed bug.
Another file forgotten
New line algo for lights
Light now fallsoff according to tile contents (water for now only)
light.lua: more help, changed screen exit key to '`'. Made it recalculate only when needed.