neutrino.custom.eslintrc in lint presets don't output correct eslintrc json

[timothyquach]

I've tried getting neutrino linting presets to output hints to vscode and found some bugs.
neutrino.custom.eslintrc throws an exception because a global is undefined and assumes options.envs is an array of objects.

[eliperelman]

According to the docs, the rc file doesn't take envs like CLIEngine, but env, which is an object of environments to enable.

http://eslint.org/docs/user-guide/configuring