#19 Folder counts

[Owen Taylor]

Here's a real simple patch to add:

GmailAccount.getFolderCounts()

Which returns a dict of folder_name =>count. The "folders" here are a combination of the labels from
getLabelNames() and the "standard folders".

getFolderCount(folder_name) would be another possible
API for the same code.

This was desired to implement the mockup for
a desktop mail widget in:

http://mail.gnome.org/archives/online-desktop-list/2007-October/msg00010.html

[Owen Taylor]

The patch