Merge pull request #5 from philmikejones/master

Spreadsheet exercises added; changes to handout.tex (plus new build of handout.pdf)
mini update
Merge branch 'master' of github.com:Robinlovelace/smsim-course
Delete 44t@_6vQ%Y6gzbR?BrzG6kbzCN?64X4+8G
edited Phil's changes, made a load of typos and improved clarity of explanation. Section 1 is now done IMO.
Merge branch 'master' of github.com:Robinlovelace/smsim-course
first cohesive draft
some typos and final suggestions for handout.tex