Description of Problem: Users of assistive technologies need edit-text
fields named (or better still, labeled) in order to effectively use them. 
A blind Gnopernicus needs this in order to have the correct information
read to them when they tab to the edit-text field.  A user with a physical
disability using GOK needs them so that their "UI Grab" keyboard will
correctly display the name of the field (and not just "Text entry (empty)"

Steps to reproduce the problem:
<with at-poke>
0. With "Assistive Technology" support turned on on the desktop (and after
log out/in)
1. Start Evolution, get the "Enter Password for <username>" dialog
2. Launch at-poke, and "poke" at this window, and "Expand" the widget tree.
3. In the UI heirarchy tree, find the password edit-text field.  Note they
have no name or relation encoded on it.

<with Gnopernicus>
0. With "Assistive Technology" support turned on on the desktop (and after
log out/in)
1. Start Evolution, get the "Enter Password for <username>" dialog
2. Launch Gnopernicus, and press "Tab" a few times.  You'll get the
checkbox and two buttons read to you in a useful way, but not the password
field (which you would expect to be read as: "Edit text Please enter the
IMAP password for <username>").

<with GOK>
0. With "Assistive Technology" support turned on on the desktop (and after
log out/in)
1. Start Evolution, get the "Enter Password for <username>" dialog
2. Launch GOK, and choose "Activate" and "Enter Password for <username>". 
Then choose "UI Grab".  Note that you see the checkbox and buttons, but the
password field is simply labeled "Text Entry (empty)" (and not something
useful like "Please enter the IMAP password for <username>").

Suggested solution: Create a pair of AccessibleRelations: LabeledBy and
LabelFor between the static text "Please enter the IMAP password for
<username>" and the edit-text password field.