Class meta_utils::MetaParameter: I think internally this should just use a meta variable.
Member ShaderCache::configure_vertex_attributes_for_drawables_vao (GLuint vertex_attribute_object, GLuint vertex_buffer_object, ShaderType type, ShaderVertexAttributeVariable shader_vertex_attribute_variable): make sure that the vertex attribute variable is actually used in the selected shader type
Member vertex_geometry::generate_square_vertices (float center_x, float center_y, float side_length): Note that the triangles are done in clockwise ordering meaning they are back-facing so if you have culling turned on they will not show up. We should probably just make them counter-clockwise so that this doesn't occur.