Introduce DOT built-in function.

[Masayuki Takagi]

We introduce DOT built-in function for the dot product operation for vector types to implement nbody sample code #4 .

For example, the dot product of two float3 vectors a = (a1, a2, a3) and b = (b1, b2, b3) is defined as:

(dot a b) = (+ (* a1 b1) (* a2 b2) (* a3 b3))

We provide the DOT built-in function for the following vector types:

• int2
• int3
• int4
• float2
• float3
• float4
• double2
• double3
• double4

We need to add related definitions in the following layers:

• Lisp built-in table
• CUDA built-in table
• CL-TUPLES operators
• CL-CUDA kernel functions