Add slats module, more icons, spacing adjustments

+ .slats metadata module
+ more icons for .slats and for channel/category tags for resources
+ allow last grid item to grow to fill width of container
+ reduce .links spacing
+ cut down on pointless comments in _oslc.scss
+ add .links.tightened with even tighter spacing
+ modify spacing of bylines and tags
+ fix for old Safari and tags with .flags (wtf??)

related to issue #7