Merge pull request cocos2d#6919 from dabingnn/v3.1hotfix

V3.1hotfix

Merge pull request cocos2d#6892 from samuele3hu/v3_fix

Update the OpenGL lua binding and related test case

cocos2d-x v3.1-rc0

cocos2d-x v3.1 alpha1

Merge pull request cocos2d#6569 from dumganhar/download-progress

Updates download-deps.py, invalid content header check

Merge pull request cocos2d#6356 from Dhilan007/develop_v3

fixed drawDebugData of LabelBMFont/LabelAtlas.

Merge pull request cocos2d#6287 from minggo/update-version

update version information

Merge pull request cocos2d#6099 from dumganhar/develop

Fixed copying resource fails in empty-lua-test.

Merge pull request cocos2d#5831 from nutty898/master_nutty_modify_fra…

…mework_modifyname_ui

Rename namespace ui->gui

Merge pull request cocos2d#5821 from CocosRobot/update_cocosfiles_139…

…4819251

[AUTO][ci skip]: updating cocos2dx_files.json