Update ruby-json-pure pacakge to 1.1.3.

2008-07-10 (1.1.3)
  * Wesley Beary <monki@geemus.com> reported a bug in json/add/core's DateTime
    handling: If the nominator and denominator of the offset were divisible by
    each other Ruby's Rational#to_s returns them as an integer not a fraction
    with '/'. This caused a ZeroDivisionError during parsing.
  * Use Date#start and DateTime#start instead of sg method, while
    remaining backwards compatible.
  * Supports ragel >= 6.0 now.
  * Corrected some tests.
  * Some minor changes.

(taca)