Cascade slide ball's opacity and the Slider's
Also cascade the colours
reuse file utils when resolving video path (ios)
[AUTO][ci skip]: updating cocos2dx_files.json
Merge branch 'v3' into patch-12

Conflicts:
	cocos/ui/UISlider.cpp
Fix formatting
Fix build for ios
Fix spacing
Merge pull request #7671 from CocosRobot/update_cocosfiles_1407234193

[AUTO][ci skip]: updating cocos2dx_files.json
Merge pull request #7675 from darkdukey/chore/reuse-file-utils-for-video-path

Chore/reuse file utils for video path
Merge pull request #7674 from darkdukey/patch-12

Fix opacity for Slider
[ci skip]
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into v3_module