Update Interactions API & General Housekeeping

Updated Interaction API & Housekeeping

API Breaks

• The Interaction API has changed. Rather than calling Interaction(component..).registerWithComponent, now you create the interaction with var interaction = new Interaction(...) and then attach it to a Component using Component.registerInteraction(interaction).
• Additionally, Interaction.Clicks now have a consistent callback api that uses Points.

API Extensions:

• Plot.attr now exists as an alias to Plot.project, and is the preferred invocation as it matches D3 semantices for the function of the same name.

Bugfixes:

• Formatters.percentage behavior is improved.
• Autodomaining no longer fails if the data is of an incorrect-but-coercible type.

Housekeeping:

• Component.renderTo(selection) now gives helpful error messages if something goes wrong.
• README updated
• Bower/NPM flavor text improved
• Examples directory removed, as it is redundant with the website
• StandardChart removed, as it is redundant with Chartographer.js