Added cli argument for tab width.
Incorporated pull request comments.

* Added in --help flag.
* Restored indentation to 2 spaces
* Made "tab_stops" consistent
* Restored default cli behavior.
Preserve formatting inside a pre element
Merge pull request #13 from jirutka/patch-4

Preserve formatting inside a pre element
Add newlines after block-like elements
Merge pull request #14

Add newlines after block-like elements.
Merge pull request #8 from musicist288/master

Added cli argument for tab width.
Remove warning when building gem
Version 0.0.11

* Preserve formatting inside <pre>
* Add newlines after block-like elements
* Add command-line option to specify tab stops
Improve Beautifier's interface

Writing directly to standard output is less useful than having a
sensible interface.

Before:

    output = ''
    HtmlBeautifier::Beautifier.new(output).scan(html)

After:

    output = HtmlBeautifier.beautify(html)