Merge pull request #25 from samuele3hu/master

Add `How to Debug a Lua Game` for 11 chapter
improve BMFont
modify label ttf
fix indentation
Update 3.md

- adding hyperlink into each of Appendix.
- changing Appendix reference for 'Creating A New Example Project'.
finish all the label parts
add menu docs
modify menu item part
add more document to TextFieldTTF
modify some texts
Merge pull request #26 from kr15to/patch-7

Update 3.md
improve document
Merge pull request #27 from andyque/master

add more docs to UI chapter
Merge branches 'master' and 'master' of https://github.com/chukong/programmers-guide