Merge pull request #2 from CdLbB/master

Some small typos fixed in Chapter 6
More work on 7.6
More work on 7.6
Finished 7.6
Start work on 7.7
More work on 7.7
More work on 7.7
More work on 7.7
More work on 7.7
More work on 7.7
Finish work on 7.7
Start work on 7.8
More work on 7.8
More work on 7.8
More work on 7.8
More work on 7.8
Finish work on 7.8; start work on 7.8.1
More work on 7.8.1
Finish 7.8.1
Start work on  7.8.2