Corrections to the report plus some stuff

Changes to gitignore to accomodate the new list of figures and list of
tables.

Also updated the bibliography with more papers and links.

The script `yearly_papers.m` generates a very crude plot of the number
of papers published between 1975 and 2009 containing the keyword
"natural language processing", corresponding to the image
`yearly_papers.png`.

Lots of changes were made to the schedule as well, but nothing really
significant -- mostly improved wording.