Add rfc search feature

The RFC search feature has a map from section title to url.
It uses difflib's fuzzy matching to find a section title corresponding
to the input, and then sends the URL of the section title back.

 data/rfc.data  |   83 ++
 data/rfc.txt   | 3531 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 plugins/rfc.py |   39 +
 3 files changed, 3653 insertions(+)
 create mode 100644 data/rfc.data
 create mode 100644 data/rfc.txt
 create mode 100644 plugins/rfc.py