Merge pull request #62 from Ivenyang/master

fixed #3305, add chapter7 sample code.
issue #3493, correct grammar,  correct doc coding style.
Merge pull request #63 from u0u0/master

issue #3493, correct grammar,  correct doc coding style.
modify the title of JSB doc
issue #3347, min.js have not include chipmunk, fix running error.
issue #3350, min.js have not include chipmunk, fix running error.
Merge pull request #64 from u0u0/master

issue #3347, min.js have not include chipmunk, fix running error.
issue #3493, fix Cocos2-html5 2.2.1 music play bug.
issue #3375, add sample code for chapter 8.
issue #3435, add sample code for chapter 9.
issue #3493, add sample code for chapter 10.
Merge pull request #65 from u0u0/master

add sample code for chapter 8, 9, 10
issue #3278, correct grammar, correct doc coding style.
Merge pull request #66 from u0u0/master

issue #3278, correct grammar, correct doc coding style.
modify spell, coding style.