Update 3.md

- adding hyperlink into each of Appendix.
- changing Appendix reference for 'Creating A New Example Project'.
Merge pull request #26 from kr15to/patch-7

Update 3.md
Update 5.md

minor modification to improve readability.
Update 6.md

minor modification to improve readability.
Merge pull request #27 from andyque/master

add more docs to UI chapter
Add content for chapter 11 about `Memory Management`
Merge branches 'master' and 'master' of https://github.com/chukong/programmers-guide
Physics Chapter
update physics
Merge pull request #28 from kr15to/patch-8

Update 5.md
Merge pull request #29 from kr15to/patch-9

Update 6.md
Merge pull request #30 from samuele3hu/master

Add content for chapter 11 about `Memory Management` and `Subclass Inherit from c++ Classes Bound to Lua`
Merge pull request #31 from Dhilan007/master

Physics Chapter
remove cocos2d namespace
Merge remote-tracking branch 'refs/remotes/upstream/master'