Use default Ruby version locally

Assume that each developer can keep their local Ruby version up to date
instead of mandating a particular one and chasing after the facts all
the time.
Consider block parameter for DuplicateMethodCall

This catches cases like the following:

    foo {|a| a.bar}
    foo {|a| a.bar}

In addition, the following cases become extra smelly since the whole
iterator is considered smelly, in additon to `foo.bar`:

    foo.bar {|a| a.baz}
    foo.bar {|a| a.baz}

One consideration is whether the following case should still be
considered smelly:

    foo.bar {|a| a.baz}
    foo.bar {|a| a.qux}

With the present change, this case stays smelly as it was before.
Update README

* Use bundler in test running examples
* Use Markdown's numbered list
* Wrap long lines
Update gemspec

* Fix dependency versioning warnings
* Fix license warning
* Improve description formatting
* Remove post install message
Merge pull request #278 from troessner/update-readme

Update README
Merge pull request #273 from troessner/remove-ruby-version

Use default Ruby version locally
Merge pull request #277 from troessner/fix-gemspec-warnings

Update gemspec
Make reek run warning-free

Enables warnings during the spec run, and fixes the following warnings:

* 'circular require considered harmful' due to some needless requires
* 'copying extra states' warning when using Hash#reject
* 'character class has duplicated range' warning due to using match
  matcher with a string argument
Merge pull request #283 from troessner/circular-dependencies

Make reek run warning-free
Merge pull request #274 from troessner/duplicate-block-method-call

Consider block parameter for DuplicateMethodCall
Added html file output

Fixed some problems

Fixed more things
Merge pull request #285 from SkuliOskarsson/html_output

Added simple HTML output
Changed from erubis to erb
Merge pull request #288 from SkuliOskarsson/erubis-to-erb

Changed from erubis to erb
Refactor unused parameters smell detector

- Remove excessive constants
- Clarify method names