log model diff on model edit
fix pep8
add testcase for host diff mixin
log model diff on model edit
fix pep8
add testcase for host diff mixin
Merge branch 'feature/changelog_model_diff' of github.com:pgolm/fwadmin into feature/changelog_model_diff
Merge pull request #35 from pgolm/feature/changelog_model_diff

log model diff on model edit