Use author rather than commiter

Hi there,

I was comparing the results of my pretty git log alias command and the one of **GV** and I noticed, in case of a topic branch on which I performed a rebase, than the dates were not equivalent.

I'm using `%ad` in my alias, which is the `Author date` field while **GV** uses `%cd`, aka `Commiter Date`.

I was perusing my history to solve a deployment issue by pinpointing the end of a specific phase of work I had been doing on a feature before it was deployed for testing.

I realize that this is mostly the result of me not mastering the workflow, albeit peculiar to me, of this project. Still, since I'm often rebasing to present a work as neat as possible for pair review, the `Committer date` is not the information I'm interested in.

What are your thoughts on this ? Would you be strongly opposed to changing the format from `Commiter date` to `Author date` ?

Thanks for your time !