[model][xs]: remove manifest_version which is replaced by profiles.
[#147,ux][m]: heavy refactor of site layout and project layout to be cleaner - fixes #147.

* Borrow heavily from prose layout
* Projects page: scripting and readme are hidden by default
[#147][s]: some futher minor css tweaks to brand.
[#147][s]: some more css tweaks.
[#52,doc][s]: start on basic guide.
[#147][xs]: fix breakage on load page caused by recent css changes.
[bugfix][xs]: correct datapipes url for loading csv (had broken due to changes on datapipes).
Merge branch 'master' into gh-pages