Support ESLint 3

No new rules were introduced in ESLint 3, and the differences between 2 and 3 do not affect this package. Updated the dev dependencies to include ESLint 3 so we can continue monitoring for changes (e.g. possible new rules) using Greenkeeper.io.

Testing and tooling

For development purposes, this release adds a very small test suite and integration with Greenkeeper.io (a dependency version updater).

Docs and ES6 support

Apart from small documentation copy edits, the most significant aspect of 1.1.0 is the addition of es6 as a default environment. This was to support the use of certain ES6 syntaxes that are now supported by Node itself but do not appear to be supported by ESLint's Node environment flag.

Bugfix: path.join

Despite saying that path.join does normalization, it appears "same-directory" syntax of ./ does not work across all environments. Dropping the preceding ./ in the config file location enabled this package to work on at least one computer. This release adopts the more universal / reliable path definition.