Restore stuff removed from .gitignore.

Restore stuff removed from .gitignore.

Committed: https://code.google.com/p/dart/source/detail?r=12462

[Bob Nystrom, 2012-09-12 20:33:37]

I see https://chromiumcodereview.appspot.com/10914176/ removed a bunch of stuff
from the .gitignore files, I guess to keep it in sync with what SVN ignores?

This has the side of causing lots of stuff that was correctly being ignored to
now show up as needing to be checked in in my client. This patch makes those go
away.

Is this OK? Is there something I need to do to get SVN in sync with this?

[ahe, 2012-09-13 06:24:06]

I think this should be done by adding the equivalent ignores to svn. As far as I
know, this cannot be done from git.

[Bob Nystrom, 2012-09-14 17:59:27]

Add some comments that auto-generating is preferred but still hand-add the stuff
that svn doesn't seem to handle.

Is this OK? I really don't want to waste any more time on this. I just want to
have a client that isn't a disaster in git. The patch that blew away the old
nice, clean .gitignores created a problem for little benefit that I can see.

[Anton Muhin, 2012-09-17 14:24:37]

lgtm