jeremy/centre: some more
some papers/books: krause, benson, g-m
gelfand-manin/derived.tex: new; notes on ch 3 (derived category)
benson/varieties: New; notes on benson vol.2 ch.5 Varieties for modules
benson/varieties: first half of 5.3
Merge branch 'master' of https://github.com/wollollo/Maths