bullet: Streamline bundling, remove extraneous src/ folder

Document version and how to extract sources in thirdparty/README.md.
Drop unnecessary CMake and Premake files.
Simplify SCsub, drop unused one.

thirdparty/bullet/Bullet3OpenCL/ParallelPrimitives/b3BufferInfoCL.h

@@ -0,0 +1,19 @@
+
+#ifndef B3_BUFFER_INFO_CL_H
+#define B3_BUFFER_INFO_CL_H
+
+#include "b3OpenCLArray.h"
+
+
+struct b3BufferInfoCL
+{
+	//b3BufferInfoCL(){}
+
+//	template<typename T>
+	b3BufferInfoCL(cl_mem buff, bool isReadOnly = false): m_clBuffer(buff), m_isReadOnly(isReadOnly){}
+
+	cl_mem m_clBuffer;
+	bool m_isReadOnly;
+};
+
+#endif //B3_BUFFER_INFO_CL_H