[1541] Add empty alt tag to gravatar

[rossjones]

Adds an empty alt tag to the gravatar link generated by helpers to fix #1541

[rossjones]

Should include something in the alt tag. 'gravatar' suggested

[mwainwright]

I disagree. The alt text is a text alternative to the picture of my gurning face. But the gurning face is purely decorative (it's linked to profile, my name also appears in the link) so reading in text mode, I don't need anything there. See

http://www.w3schools.com/tags/att_img_alt.asp

[rossjones]

Well the PR is there to do what you want, I'll let you convince the others are to whether is should really be blank (in which case it added nothing), or gravatar, or the user's name.

[nigelbabu]

So, are we closing this or merging?

[seanh]

@rossjones Suggest alt text "Sean Hammond's gravatar" and then we should merge this. This doesn't fix #1541 though

[amercader]

Just merged it with an empty alt="" as the full name was not trivial to get from the function and I don't want to change its params. If someone feels strongly against it feel free to send a new PR.