function debounce and throttle

1. use ternary operator if value then val1 else val2
2. use `else if ` in coffeescript
Finish chap 7

1. A partial of Chap 5 and totally Chap 6 is skiped (lot about algorithm)
2. Finish chap 7
Finish Char 9

1. skip jQuery plugin and AJAX because i am not familiar with jQuery
Finish Chap 12

1. skip verbose of this chap
2. ship rest chaps