Some Release Notes cleanup.

- Don't list bugs which were fixed in 1.12 as being fixed in 1.99. (We probably
  should add some bugs to the bugs-fixed list.)
- Remove new-features list for everything prior to 1.12 (so we only list
  improvements since 1.12).
- Fix bug link to bug 1814.
- Fix the wiki's URL (the wiki doesn't appear to support https today).
- Remove bugs 4445 and 9242 from the Known Problems list: they've been fixed.

Change-Id: Ideb9ddf24e429ee00c19ac975370aa4fe81e652b
Reviewed-on: https://code.wireshark.org/review/4403
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>