Add wield light
Merge remote-tracking branch 'Zeg9/wieldlight'
Add wield light
https://github.com/minetest/minetest/pull/816

Conflicts:
	client/shaders/test_shader_1/opengl_fragment.glsl
	client/shaders/test_shader_2/opengl_fragment.glsl
	client/shaders/test_shader_3/opengl_fragment.glsl
	freeminer.conf.example
	src/defaultsettings.cpp
make wield_light group based