Merge pull request #2 from Kaffeine/master

Fixed hardcoded boost-python library reference.
Move object hierarchy to smart pointers.
Python garbage collecting now working without problems.
Some minor fixes in Engine class.
Focusing functions using smartpointers.
Started porting to SDL2.
Fix building on windows using MSVC.
Continue porting to SDL2
Start menu widget.
Python wrappers rewritten.
Improve cmake scripts.
Settings widget.
LineEditWidget -> LineEdit.
Tools ported to Qt5.
Fix building on Mac OS.
Python bindings to World.
Add missing CMakeLists.txt
Remove old lua scripts.
Smart pointers in python bindings.
Improve NinePatch.
Ninepatch now supports tiled texture in patches.
Fix converting pixels to texture coordinates.
New info widget.
Fixed typo in CMakeList.