Change the word "Meeting" to "Event" in Sign up tool for Great Britain users

The word 'meeting' should be replaced by 'event' in the sign-up tool as we use it for heaps of other events.

The tool is peppered with the word and it is also included in emails.

Sign-up notification emails look like:

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Dear Jill ,

You have signed up for the following meeting in the "robstest" site on
WebLearn:

Meeting Title: Interview 2
Time slot: 09:00 - 10:00 on 19-Apr-2013
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There is no need to include the word meeting as it is too specific and the thing that one has signed up for may not be a meeting; use event or miss out the word instead.

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Dear Jill,

You have signed up for the following event in the "robstest" site on
WebLearn:

Title: Interview 2
Time slot: 09:00 - 10:00 on 19-Apr-2013
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