Add more default excludes

Signed-off-by: Paul de Wouters <paul@hmn.md>
Merge branch 'master' into feature/486-exclude-directories-default
Exclude BackUpWP by default

Signed-off-by: Paul de Wouters <paul@hmn.md>
Fix typo in prefix
Merge pull request #486 from humanmade/feature/486-exclude-directories-default

Additional backup directories to exclude