Convert DOS (CRLF) source files to Unix (LF) line endings

Excluded `examples/pybullet/gym/pybullet_data/` which has many (3000+)
CRLF data files (obj, mtl, urdf), and `docs/pybullet_quickstart_guide`
which has generated .js and .htm files with CRLF line endings too.

src/BulletCollision/NarrowPhaseCollision/btGjkPairDetector.cpp

@@ -1,4 +1,4 @@
-/*
+/*
 Bullet Continuous Collision Detection and Physics Library
 Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/