Fix possible deadlock on sigint
Less messages
Add FORCE_LEVELDB because with nuget we don't have leveldb lib/include.

Conflicts:

	build/windows/build.py
	src/CMakeLists.txt
Optionally display console on Windows (via config option) (fixes #54)

Conflicts:

	src/defaultsettings.cpp
	src/main.cpp
Some refactoring
Remove circuit nodes duplicates from games/minimal/mods/default/init.lua
Remove circuit elements textures duplicates from games/minimal/mods/default/textures/
Initial support of 6d facedir + some refactoring.
Bug fixes + Some refactoring.
Add license headers
Add more circuit elements