[Ecls-list] More changes

[Juan Jose Garcia-Ripoll]

Hi,

I have committed another 9 patches regarding error handling in ECL.
They mostly include a new function ecl_fixnum_in_range() which ensures
that the input is a fixnum between two specific values. This is being
used in many other functions. Apart from that, two fixes:

 - Reader for #( did not always read the last parenthesis, what lead
to a warning:
        > #3(1 2 3)
        #(1 2 3)
        > ;;; Warning: Ignoring an unmatched right parenthesis.

 - DIGIT-CHAR-P and DIGIT-CHAR will signal an error if the radix is not an
   integer value between 2 and 36, both included.

Regards,

Juanjo