[make] various rule tweaks to expose deps better
[site] remove generated droppings
[unikernel] remove unnecessary method
[server] pass around uri rather than request

removes need for `http_uri` method in record
[git] ignore more droppings
[store] coffee 1.8 is stricter; so fix typo
[make] whitespace; do better about `FS=fat` dependencies
[site] use ``` `Html ``` where we used to use ``` `Page ```
[assets] add dummy favicon.ico
[blog] add text for post about mirage on Xen
[make] split out env vars
[git] ignore fats