NEW - rasql supports overlay in rasql general condenser and supports multiple axis iterators variables

[Bang Pham Huu]

rasql, by default it iterates ascending but can be controlled with ASC/DESC keywords:

condense overlay
over i in [0:2] DESC
using A[i,*:*,*:*]

The general syntax is

    condense condenserOp
    over var in mintervalExp [ASC|DESC]
      [, var in mintervalExp [ASC|DESC] ]...
    where booleanExp
    using cellExp

After this patch is done in rasql, then assign to BPH for implementing in petascope.