Make list-item's display style block
Cleanup attribute setting functions a bit.
Make Attr::local_name always initialized.
auto merge of #1249 : Ms2ger/servo/set-attr, r=kmcallister
auto merge of #1251 : Ms2ger/servo/attr-localname, r=kmcallister
auto merge of #1254 : pcwalton/servo/rule-hash, r=pcwalton

This is @pradeep90's PR with one little optimization.
auto merge of #1231 : sonwow/servo/list-item, r=SimonSapin
WIP for new box building
WIP for incremental reflow
More work on {ib} splits
Float WIP
WIP before removing "floated inline" bogosity
Fix box building