AddThis - Implement AddThis feature in the RVE

This is part 2. of the spec. http://www.curriki.org/xwiki/bin/view/Project/MetricsSpecs

2. Implement the AddThis feature in RVE
a. Maintain the current Email icon
b. Change the name of the "Email" link to "Share" (Trans update)
c. Maintain existing rules for when the "Email" link appears to members vs visitors
d. When a user hovers or clicks on the "Email" link/icon in RVE, they should be able to utilize the AddThis feature

RVE = Resource View Edit. Here is an example. http://www.curriki.org/xwiki/bin/view/Coll_ShermanTank/WikiForm

Note: Chrissie will make all Trans changes.