Bump Lato Webfonts to v2.0

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Update Sass vars to treat Lato as true font-family

Declare Lato weights appropriately.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Fix lack of real italic: add Lato italic fonts

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Merge pull request #1174 from opf/fix/lato-faux-italic

Fix OpenProject's use of faux italic, Upgrade to Lato v2.0