add Hight function

all wagering web or project new countdown, also highlight
the race which is close to jump.
*tear down close time to 5m/15m highlight
*add test cover
change class name to easy and clear

some class or method name not says to understand
change it to more clear
Merge pull request #2 from frontfoot/feature/hightlight-close-time

add Hight function to close time