Cookie size limit handling is wrong

In 1.7 some new cookie handling was introduced. Specifically, it deletes datatable cookies if the *total* size of cookies is larger than 4Kb. This is not correct. The cookie size limit of 4Kb is *per* cookie and not the sum of cookie sizes. This limit is easily hit if using several large-ish datatables.

Documentation of cookie size limits here:
http://www.ietf.org/rfc/rfc2109.txt (6.3 Implementation Limits)

I believe the entire loop that deletes cookies in _fnCreateCookie() should be removed.