[Fix #1000] Support modifier and def on same line in IndentationWidth

Enforce an indentation style for Ruby >= 2.1 when "private def" etc
is used.
[Refactor] Shorten IndentationWidth

Needed to make it pass rubocop inspection with ClassLength/Max 121.
Add `UnneededCapitalW` cop

Add new cop `UnneededCapitalW` which detects usage of %W when
interpolation is not needed and %w would so.  Does not yet do
autocorrect.
Corrections to UnneededCapitalW

Adding Changelog entry and spec.
Add `UnneededCapitalW` cop

* Add new cop `UnneededCapitalW` which detects usage of %W when
  interpolation is not needed and %w would so.  Does not yet do
  autocorrect.
* Adding Changelog entry and spec.
* Add UnneededCapitalW to enabled.yml.
* Fix spelling of useage in percent_literal_delimiters.rb
[Refactor] Extract module OptionsHelp from Options

Put all help texts in one place.
[Refactor] Move methods from ConfigLoader to Config

Takes care of the code smell "Feature Envy" in ConfigLoader and
makes it smaller. Two birds with one stone.