Added emacs local variables to subsidiary files
Added placeholder macro
Added source page number annotations
Added pre-intro summary of Ch.1
Added some style, reference guidelines to README.
Initiated signup sheet
Added mathpartir package (for inference rules; not in standard distributions).
Completed 1.1 (and added relevant macros, updated signup sheet, etc.
Added style notes re itemised/numbered lists
Added missing source page ref
Added section titles to complete document outline
Fixed typo.