Update to 1.2.1

Changelog:
Version 1.2.1 <2013-10-16>
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  * fixed loading images with relative path

Version 1.2 <2013-09-20>
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  * added initial support of animations
  * added support of mask for image element
  * removed obsolete backends (libart and agg)
  * removed svgui classes

Version 1.1.16 <2013-08-25>
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  *  rendering: added support of wxProgressDialog

Version 1.1.15 <2013-05-01>
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  * fixed text rendering using PangaCairo

(ryoon)