12.6.0

• Bugfix: btTriangleShape::isInside() relies on the plane normal, which is invalid for a degenerate triangle
• Bugfix: unsafe normalize() is used in btTriangleShape
• Bugfix: typo in btTriangleShape::isInside() ("distance" for "distance2")
• Pending resolution of Travis CI ticket #34567:
  • Upgraded MacOS64 build tools from Xcode 9.3 to Xcode 12.4 .
  • Dropped support for the MacOSX32 platform.
• Added the isInsideTriangle() method to the NativeLibrary class.
• Upgraded the Bullet sources to match SHA1 ID=10f72b9b5 of the bullet3 project.