 allocmis - allocates and initializes an mis structure with specified
            attributes and length.
 reallocmis - reallocates or allocates if necessary an mis structure
              with specified attributes and length.
 appendmis - takes an image raster and appends it to the end of a
             homogeneous size and depth mis structure.
 changemis - overwrites a specified entry in an mis structure with
             the image passed.
 deletemis - removes an mis entry at the specified position and shifts
             all the following entries to fill the empty position.
 freemis - deallocates the memory associated with the specified
           mis structure.
 freemishdr - deallocates the header associated with the specified
              mis structure. Only used after a call to readmishdr.
 buildmishdr - given a list of mis attributes, returns a new
               allocated and initialized mis structure.
 readmisfile - reads the contents of the specified file into a new
               mis structure.
 readmishdr - reads the IHead information from the specified file into a
              new mis structure.
 writemisfile - writes the contents of an mis structure to the
                specified file in IHead format.
