use YAML instead of JSON for portfolio data

[clhenrick]

...because it's more human readable & easier to edit in a text editor.

Conversion:

• https://www.npmjs.com/package/json2yaml
• http://www.json2yaml.com/

[clhenrick]

but need to be careful of double quotes: http://stackoverflow.com/questions/19109912/do-i-need-quotes-for-strings-in-yaml