tools: enable whitespace related rules in eslint
tools: enable whitespace related rules in eslint

Enables rules for trailing whitespace, final newline and maximum
consecutive empty lines.

PR-URL: https://github.com/nodejs/io.js/pull/1971
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node