walls should use the username by default

[simonpkerr]

at present, default walls are just called 'my memory wall.' These need to be more personalised. Maybe use the username, an 's after it, then a random adjective (groovy, funky, cool, nice etc) then 'memory wall,' which would make them more fun. also, assign a random image that the user can then change. this would make the gallery more appealing.

[simonpkerr]

updated walls so that default walls and created walls automatically have a default random name based on either the user name or first name. still needs testing.

[simonpkerr]

finished testing