Update the calling convention for all external facing functions. By
external facing, I mean all functions that are directly referenced in
cube.sql. Prior to my update, all functions used the older V0 calling
convention. They now use V1.

New Functions:

cube(float[]), which makes a zero volume cube from a float array

cube(float[], float[]), which allows the user to create a cube from
two float arrays; one for the upper right and one for the lower left
coordinate.

cube_subset(cube, int4[]), to allow you to reorder or choose a subset of
dimensions from a cube, using index values specified in the array.

Joshua Reich