Add normalize_url option

ref: #110

metainspector can't access This page.

[Template:～ - Wikipedia](http://ja.wikipedia.org/wiki/Template:%EF%BD%9E)

But, another HTTP Client can access it.

```ruby
require 'metainspector'
require 'open-uri'
require 'httpclient'
require 'faraday'

url = 'http://ja.wikipedia.org/wiki/Template:%EF%BD%9E'

# metainspector
puts MetaInspector.new(url).response.status #=> 404

# open-uri
puts open(url).status #=> 200

# httpclient
puts HTTPClient.new.get(url).status #=> 200

# faraday
puts Faraday.new(url).get.status #=> 200
```

This issue is caused URL normalization. This patch allows you to disable URL normalization by option.

```ruby
MetaInspector.new(url, normalize_url: false)
```