added lab6
Merge branch 'master' of https://github.com/michaelghay/cosc460
fixed minor bug in Transaction
modified TransactionTest systemtest so that it flushes all pages on commit -- this way students can still pass this before before they have implemented recovery
changed Transaction.java back!
Merge branch 'master' of https://github.com/michaelghay/cosc460
done with lab 6 milestone 1