Fixes the data context on the member popover in the details pane. Also
change the way Popover detect if the click is initiated from a parent
popover -- from reading Blaze context, to looking at the event target
parents.
The user is now able to upload an avatar, and pick one in a list.
This functionality should eventually be abstracted in a community
package but we still need to work on a great public API. We rely on
collectionFS to manage uploaded avatars. We also removed
bengott:avatar which was trying to solve the wrong problem (namely
displaying the avatar, which is as simple as displaying an image), and
not a avatar system as it should be.
Gravatar support is coming (back) soon. We may also want to have a
list of default fun avatars the user can choose instead of uploading
its own one.
