add command to branching description
include using git diff
add exercise to fetch and merge
add note about avoiding git pull
minor tidy up
add note about short status
add exercise to delete a branch
Merge pull request #4 from donal/add-delete-branch-notes

add exercise to delete a branch
change year
Merge remote-tracking branch 'origin/master'

Conflicts:
	README.md
add exercise to handle merge conflict
add exercises to view log
use an ordered list
add git stash exercise
add pdf of slides
add link to slides in README
fix link to slides
update slides
update slides from feedback
Merge remote-tracking branch 'origin/master'