More time to specify username mapping

[GoogleCodeExporter]

This is probably more of a GitHub issue, but I don't know where to report it to 
them and I see that you forward stuff here to them where suitable, so I'll 
report it here.

I noticed that once you start the export to GitHub, you can, although not 
advertised anywhere, go to the GitHub import tool and specify the username 
mapping to GitHub users.

Steps:
1. Say you export my project "altdrag" using the export tool.
2. Then once the export has begun, navigate to 
https://import.github.com/stefansundin/altdrag/import (replace with your 
username)
3. You may have to refresh if the import hasn't begun yet. Keep refreshing 
until you can see it doing the import.
4. Usernames show up below and you can map them to GitHub users.

Unfortunately, once the import has fetched all the commits, you can briefly see 
the status "Updating authors", and after which, any changes to the mapping 
doesn't have any effect. It would be nice to have a few extra minutes to update 
this information correctly. Doing it afterwards is painful and involves git 
filter-branch commands.

In addition, the mapping form should probably be disabled when changes stop 
having effect.

It would be awesome if you guys could forward this to the appropriate person. 
Thank you!

Original issue reported on code.google.com by recover89 on 17 Mar 2015 at 3:59