[Feature] Import tags the same as categories

[stephenyeargin]

Noticed that the module can import categories, but not tags. This would be a somewhat easy addition. The WXR format accommodates both, with a change to the domain= attribute in the XML.

A category

<category domain="category"><![CDATA[New Category]]></category>
<category domain="category" nicename="new-category"><![CDATA[New Category]]></category>

A tag

<category domain="tag"><![CDATA[New Tag]]></category>
<category domain="tag" nicename="new-tag"><![CDATA[New Tag]]></category>

I took a swing at updating the CoffeeScript, but wasn't able to figure out how you were compiling the ./lib/*.js files.

[stephenyeargin]

Fixed by #3. 🎉

[f1nnix]

Hi @stephenyeargin, thanks for contributing to node-wxr. Sorry for delay, I review and accept PR ASAP.

[stephenyeargin]

@f1nnix Bumping for another look. 😸