code formatting
fixed iter_array which returning "masked" when use_mask was False
wrapping and unwrapping not capturing masked grid values #323

Wrapping now uses the data attribute of the masked arrays on the
grids. Also changed the array iterator on the geometries to not
use the mask though this was redundant as the data attribute was
already being used.
shapefiles names beginning with integer break sql expressions #325

SQL expressions for selecting geometries is no appropriately
quoted.
Merge branch 'next' into i317-basis-comparison
mark - changes to compute to handle basis functions