Version 1.5

Version 1.5:

• Add support for specular maps and normal maps, including
  in the JSON mesh format and MTL material format.
• To support normal maps, extra methods for bitangents and
  tangents were added to the Mesh class.
• Added six new demos and modified several others
• Support 24-bit color versions of TGA files
• Scene3D now does frustum culling of its shapes
• Fixed vertex normal calculation in the recalcNormals()
  method of the Mesh class.
• Allow two-element arrays to be passed to the Mesh class's
  texCoord3() method.
• Add getBoundingBox method to the Mesh class.
• Add the setVisible method to the Shape and ShapeGroup
  classes.
• Allow reading OBJ files with negative reference numbers
• Add path.js (2D graphics paths) to extras
• Added an "axis" parameter to the SurfaceOfRevolution
  constructor and fromFunction method
• Add vec3negate, vec3negateInPlace, vec3mul, and plane
  and frustum methods to the GLMath class
• Deprecate the practice of setting shape materials directly
  to textures (calling the Shape#setMaterial method with a
  Texture object rather than a Material object).
• Deprecate certain properties of Transform that shouldn't
  be exposed as a public API and add corresponding methods
  for those properties
• Fix getPromiseResults
• Documentation added in many places
• "meshexamples.md" demo added and other demos edited
  or rearranged
• Other changes and fixes