Log Message:
Update ruby-rcairo to 1.5.0.

Release 1.5.0 (2007-05-27) Kouhei Sutou <kou@cozmixng.org>)
==========================================================

Many API improvement.

Features
--------
  * Support Cairo::Surface.new with block.
  * Support RubyGems.
  * Add experimental API Cairo::Context#pseudo_blur. (API
    may be changed.)
  * Fix strange Cairo::Context#push_group and
    Cairo::Context#pop_group behaviour.
  * Fix Cairo::Context::Path#map_path_onto.
  * Add high-level color interface. (Cairo::Color)
    * Improve color related API. For example:
        From:
          context.set_source_rgb(1, 0, 0)
        To:
          context.set_source_color(:red)

    * Support RGB/CMYK/HSV conversion.
    * Many default color definitions.
  * Support path creation using Cairo::Path without
    Cairo::Context.
  * Improve constant value specify API. For example:
      From:
        Cairo::ImageSurface.new(Cairo::FORMAT_ARGB32, 100, 100)
      To:
        Cairo::ImageSurface.new(:argb32, 100, 100)
  * Support win32 surface. (Yoshinao Muramatsu)