Improve example packages

Acceptance criteria

[x] we have few (2-3), but good example data packages that are clear and easy to understand of how to create desired views
[x] Any new user can easily add desired view to his/her Data Package, by just looking at the example package

[x] fix-ups according to feedback on existing ones
[x] Choose 3 example package and make it ideal
[x] change titles for packages to be simple and clear - describing what tutorial is for
[x] nice intro/summary in README
[x] datapackage.json embedded
[x] step by step explaining how to create views for package
[x] Ask someone to create views for any package according to example data package
[x] Do the same for all examples

[x] Typos
[x] Data Package is 2 words
[x] heading should be h2
[x] script tag (gist) inside README is bad idea cause of security problems
- allow to embed datapackage.json with new extension
[x] Reasonable titles for example Data Packages,
- should be easily understandable that eg: this is vega, this is simple one, this is vega super complex, etc...
[x] More description (README) on search page
[x] vega map:
- we do not support topojson, so no data is displayed for states and not even an error message or something like that.. Eg: "we do not support topo json so data can not be displayed:
- in resources we should have either name or index, both of them are confusing