fix KeyValueOserving bug. refer to issue 42
Merge pull request #55 from tsaizhenling/master

keyvalueobserver bug fix. refer to  issue 42
PERFORMANCE: made basic rendering up to 40 percent faster by tweaking Apple internal low-performance.
PERFORMANCE: added optional methods to export an SVGKImage directly into NSData or UIImage with support for Apple's internal performance-optimization / accuracy-reduction flags
Added feature for OpenGL integration: you can flip the output images upside-down to undo Apples incompatible y-axis
Now removing KVO on DOMTree.viewport in dealloc. This is added in initWithParsedSVG and never removed, which causes a leak when an SVGKImage is deallocated.
Merge pull request #56 from joeldev/master

KVO leak in SVGKImage
fix some memory leaks.
sync for thread safety
more memory leaks
increment reference count as per clang
memory leak fix
Fixed small typos and missing comments
more memory leak fixes.
Merge pull request #57 from tsaizhenling/master

memory leaks
Merge commit '11bf63b471011b15d33b74556995b0345de00145'