Fixed retina/contentScale position errors for iPhone 6+ devices in EditBox.

Problem is that factor was 1.0 or 2.0 until iOS 8 introduced 3.0.
Merge pull request #1 from cocos2d/v3

Update from cocos2d-x
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3
modify Clipping to RenderTexture Test to get correct behavior
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3
let billboard can rotate in the Z axis
performance improvement
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Modify bugs for flatbuffers
Merge pull request #9377 from dabingnn/v3.3Perf

performance improvement
Merge pull request #9381 from pipu/modify_bugs_for_flatbuffers

Modify bugs for flatbuffers
Merge pull request #9354 from huangshiwu/v3_clippingnode

modify Clipping to RenderTexture Test to get correct behavior
Merge pull request #9378 from lite3/patch-1

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Remove useless copy about luasocket on the android platform
update runtime version to 1.6
Merge pull request #9388 from cocoscodeide/v3

update runtime version to 1.6
update for cocos reader
ListViewReader completed and listview callback feature.
update for cocos reader