update git log

[chuanxd]

example

git log 
git log —online
git log —online -p
git log —oneline —stat
git log —oneline —graph

git log —until=1.minute.ago    // until
git log —since=1.day.ago       // since days
git log —since=1.hour.ago     // since hours
git log —since=1.month.ago —until=2.week.ago // since 7 until (relative)
git log — since=2000-01-01 —until=2012-12–21 // since & until (absolute)

...etc