xlink:href in Pattern element now works

It fills like a hack, but it works:
If the pattern contains xlink:href attribute then I add SVGUse element referring the original pattern. And store id of the original pattern.
At draw time I take x, y, width and height from the original pattern.
fixed pattern opacity
small bugfix
Fixed pattern attributes inheritance. Including pattern transform attribute.
fixed pattern transformation in case pattern object top-left point is not at (0,0)
Made hugely scaled patterns look better: scale them before rendering to bitmap.
self overlapping patterns
dont add inherited children to the pattern if it has it's own children
bug fix: when pattern had non-integer width or height it was rendered incorrectly
parent.numInvalidElements was not updated if  element was removed from it's parent from VALIDATED event handler. That lead to infinite document.queueValidation() call.
In particular it was the case when the element had a pattern fill. SVGPattern is attached and then detached in patternValidated function.
Merge branch 'validationbug' into patternbug
bug fixed: pattern inherited styles from element filled with it.
initial commit of the SVGRendererDFTest
Test program that can be run from FlashDevelop
Merge branch 'fdtest' into patternbug
Merge pull request #21 from romamik/patternbug

Pattern issues