missing methods in ccui.Scale9Sprite

[cruzdanilo]

isFlippedX, setFlippedX, isFlippedY and setFlippedY were removed from ccui.Scale9Sprite in c1c76b0, and it's breaking "legacy" code, even on minor updates (mine is from 3.11.2 to current). if this is the intended behaviour, the deprecated methods should be kept at least until the next major version, following semantic versioning specification, item 8:

Major version X (X.y.z | X > 0) MUST be incremented if any backwards incompatible changes are introduced to the public API. It MAY include minor and patch level changes. Patch and minor version MUST be reset to 0 when major version is incremented.