blocker-mode: Boost blocker-mode performance.
blocker-mode: Boost blocker-mode performance.

- Use a single hash-table for all blocked hosts instead of multiple lists.
  We have possibly millions of entries, hash-tables are faster than lists at
	this point.

- Don't parse on each test!  (Wow, how did we let this go through...)

- Blocked lists are loaded when the mode is instantiated or when a list is
updated, not during a request.  This won't dramatically slow down a network
request when blocker mode needs initializing / refreshing.

jmercouris/NeXT,jmercouris/NeXT