Updated README with a more general introduction.

As above
General bug fixes

Changes AllRoutines to return frequencies as an array rather than a
list; ChartWindow now has boxplots but these are not implemented yet;
ImportCSV is expanded to handle larger than memory files; ImportHTML
displays HTML characters; Inferentials has a working chi square test;
salstat has a lot of generic changes including expanding the grid when
pasting material exceeds the grid's size, ensuring inferential tests
are done properly, calling HTML imports properly, and it now closes
properly.