This commit removed functions/events that have been deprecated in Bro
2.6. It also removes the detection code that checks if the old
communication framework is used (since all the functions that are
checked were removed).
Addresses parts of GH-243
* is_valid_ip() is now implemented as a BIF instead of in
base/utils/addrs
* The IPv4 and IPv6 regular expressions provided by base/utils/addrs
have been improved/corrected (previously they could possibly match
some invalid IPv4 decimals, or various "zero compressed" IPv6 strings
with too many hextets)
* extract_ip_addresses() should give better results as a result of
the above two points
