-- Fetch articles from Pubmed by typing Pubmed("term")

Signed-off-by: Mark Farrell<m4farrel@csclub.uwaterloo.ca>
-- Added Extract(...) for streaming articles from Pubmed, extracting
knowledge from them and producing a Gexf file.
-- Deleted "Tokenize.scala"

Signed-off-by: Mark Farrell<m4farrel@csclub.uwaterloo.ca>
-- Support knowledge streaming from Pubmed.

Signed-off-by: Mark Farrell<m4farrel@csclub.uwaterloo.ca>