0.0_base.c copied as base for 2.3.1_multiple_objects_in_openGL.
Makefile copied to 2.3_Objects_in_Depth.
Object data and definitions copied from tutorial to 2.3.1*.c.
2.2.3.frag copied to 2.3.1.frag.
2.2.3.vert copied to 2.3.1.vert.
Resolution changed. Shader references changed from 3.1* to 2.3.1*.
Function initialize_vertex_buffer() rewritten.
Function display() partially extended. Variables added.
ARRAY_COUNT defined.
Extension of function display() completed.
Multiple compiling errors corrected.
Segfault omitted.

Conflicts:
	arcsynthesis/02_positioning/2.3_Objects_in_Depth/2.3.1_Multiple_Objects_in_OpenGL.c
Function initialize_program() extended with uniform and matrix.
Offset changed to reflect changes along the z-axis.