Clean up/normalise whitespace in Sass, CSS

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Merge pull request #1327 from opf/fix/stylesheet-style-fixes

Stylesheet style fixes
Make wp headline responsive to themes
Merge branch 'dev-angular' of github.com:opf/openproject into dev-angular
Merge pull request #1344 from opf/dev-angular

Dev angular