Update list of standard hooks for Git 1.8.3

Signed-off-by: Gustavo L. de M. Chaves <gustavo@cpqd.com.br>
Enhance list of hook examples

I think email notifications are best sent after a successful push. A
commit is still too early.

The pre-receive hook is extremelly useful for enforcing all kinds of
rules. I think it deserves to be in the example list.

Signed-off-by: Gustavo L. de M. Chaves <gustavo@cpqd.com.br>
Fix typos

Signed-off-by: Gustavo L. de M. Chaves <gustavo@cpqd.com.br>
Merge pull request #6 from gnustavo/update-hooks

Update hooks