Support XML as input format

[Blacksmoke16]

Let's support normal XML before starting on #7. This will lay the groundwork for the logic required to parse the XML. Altering the output JSON should then be easier.

[Blacksmoke16]

Hey @nichtich. If you had an XML document like:

<root>
  <one>  Some Data</one>
  <two>A bunch of data
  </two>
</root>

Would you expect the output to be:

{
  "root": {
    "one": "Some Data",
    "two": "A bunch of data"
  }
}

Or

{
  "root": {
    "one": "  Some Data",
    "two": "A bunch of data\n  "
  }
}

I.e. should the extra whitespace in the elements be preserved significant or just be stripped out?

[nichtich]

Following XML practice in this case (in text only elements) the whitespace is significant, so the second variant