added quick patch to allow the downcasting of array data types to the formats specified by the FORMAT argument in the Column constructor.  There really should be some error checking added to check that the downcast is allowable and safe.
added quick patch to allow the downcasting of array data types to the formats specified by the FORMAT argument in the Column constructor.  There really should be some error checking added to check that the downcast is allowable and safe.

git-svn-id: 5305e2c1a78737cf7dd5f8f44e9bbbd00348fde7@196 ed100bfc-0583-0410-97f2-c26b58777a21

embray/PyFITS,spacetelescope/PyFITS,embray/PyFITS,embray/PyFITS,spacetelescope/PyFITS,embray/PyFITS