This function appends a new token to an existing string. It returns the string plus a comma plus the new token. If the token already exists in the string, it is not added.
Takes two parameters:
The first parameter is the string.
The second parameter is the token.
<$myString = strCommaAppendNoDuplicates(myString, "A")$> <$myString = strCommaAppendNoDuplicates(myString, "B")$> <$myString = strCommaAppendNoDuplicates(myString, "C")$> <$myString = strCommaAppendNoDuplicates(myString, "A")$> <$myString = strCommaAppendNoDuplicates(myString, "B")$>