Add the old Bullet 2.x obsolete demos, and CMake buildsystem files, and gradually move them to newer Bullet 3.x structure

Use statically linked freeglut, instead of dynamic glut for the obsolete Bullet 2.x demos
Add the 'reset' method to b3GpuDynamicsWorld, and use it in the BasicGpuDemo (pretty slow in debug mode, use release mode)
Don't crash in btCollisionWorld, if there is no collision dispatcher

BulletConfig.cmake.in

@@ -0,0 +1,25 @@
+#                                               -*- cmake -*-
+#
+#  BulletConfig.cmake(.in)
+#
+
+# Use the following variables to compile and link against Bullet:
+#  BULLET_FOUND              - True if Bullet was found on your system
+#  BULLET_USE_FILE           - The file making Bullet usable
+#  BULLET_DEFINITIONS        - Definitions needed to build with Bullet
+#  BULLET_INCLUDE_DIR        - Directory where Bullet-C-Api.h can be found
+#  BULLET_INCLUDE_DIRS       - List of directories of Bullet and it's dependencies
+#  BULLET_LIBRARIES          - List of libraries to link against Bullet library
+#  BULLET_LIBRARY_DIRS       - List of directories containing Bullet' libraries
+#  BULLET_ROOT_DIR           - The base directory of Bullet
+#  BULLET_VERSION_STRING     - A human-readable string containing the version
+
+set ( BULLET_FOUND 1 )
+set ( BULLET_USE_FILE     "@BULLET_USE_FILE@" )
+set ( BULLET_DEFINITIONS  "@BULLET_DEFINITIONS@" )
+set ( BULLET_INCLUDE_DIR  "@INCLUDE_INSTALL_DIR@" )
+set ( BULLET_INCLUDE_DIRS "@INCLUDE_INSTALL_DIR@" )
+set ( BULLET_LIBRARIES    "@BULLET_LIBRARIES@" )
+set ( BULLET_LIBRARY_DIRS "@LIB_DESTINATION@" )
+set ( BULLET_ROOT_DIR     "@CMAKE_INSTALL_PREFIX@" )
+set ( BULLET_VERSION_STRING "@BULLET_VERSION@" )