Gravatar integration

If you don't already have one, go to http://en.gravatar.com/ and create one or more Gravatar accounts with one or more email addresses you control, for testing. Create (or edit) two Moodle users to use the Gravatar-assigned email addresses, one with an uploaded user picture and one without. You will also want at least two other Moodle users with non-Gravatar email addresses - one with an uploaded picture, and another without. (Alternatively, you could simply alter one user as you go, to fulfil the various testing criteria as needed). Run a site upgrade at /admin/ to pick up the new Gravatar setting (leave at the default: NO). 1. Gravatar OFF Examine user pictures (in user profile view and edit pages, in forums, course participants, etc.) to see that the existing behaviour has persisted (normal user picture, no Gravatar image). 2. Gravatar ON by default Change the Gravatar admin setting to "YES, show by default". Examine user pictures again - the user picture should now be the Gravatar image, for those users with a Gravatar-enabled email address. Moodle users without a Gravatar-enabled email address should show their picture as normal (if any). 3. Gravatar ON, but user-decided Change the Gravatar admin setting to "YES, but don't them show by default (let the user decide)". Examine user pictures again - there should be no Gravatar images, unless the user has specified to use the Gravatar image in their user profile. The user picture should be their uploaded picture as normal (or the system default if none uploaded). Change a Gravatar-enabled Moodle user to use Gravatar in their profile. This user's picture should now appear as their Gravatar image.