[sugar] Fixing activity names

[Marco Pesenti Gritti]

We need the names of the following activities fixed, per request of the 
design team.

    * Calc --> Calculate
    * Call --> Video Chat
    * Camera --> Record

Please add a comment to the ticket once you have done it:
http://dev.laptop.org/ticket/1996

This is targeted for Trial-2, so let's get all of them fixed in RC3.

Marco