step one of adding PropertySortOrder linting
fix more lint
fix lint in _posts.scss
cleanup lint in _common.scss
cleanup lint in sitenav
cleanup last lint and regen css
lock html-proofer to 1.2.1

to see if that fixes gjtorikian/html-proofer#102
Merge pull request #5 from GeoDienstenCentrum/scss-lint_PropertySortOrder

scss lint property sort order