update some new functions.
fixed demo source error
Merge pull request #277 from u0u0/master

fix catalog links
Update the tutorials to V3.0
Merge pull request #278 from linshun/master

Update the Parkour tutorials to V3.0
Removed useless link and fixed some expression.
Merge pull request #279 from linshun/master

Removed useless link and fixed some expression.
add quick folder.
Merge pull request #280 from Ivenyang/master

add quick folder.
Merge pull request #275 from honghui/master

fixed demo source error
Merge pull request #273 from hanrea/master

update some new functions.
Updated chapter 2 of parkour tutorials to v3.0
Merge pull request #281 from linshun/master

Updated chapter 2 of parkour tutorials to v3.0
fixed typo
Merge pull request #282 from linshun/master

fixed typo
updated catalog
Merge branch 'master' of https://github.com/cocos2d/cocos-docs

Conflicts:
	catalog/en.md
	catalog/zh.md
Updated catalog
Merge pull request #283 from linshun/master

updated catalog
Update en.md