XML: --Output=XmlWithAttr for more parseable conformance report

[JeromeMartinez]

This permits an easier integration in some workflows, including MediaConch (to be implemented).

Before:

<GeneralCompliance>File size 8585 is less than expected size at least 8589 (offset 0x20BD)</GeneralCompliance>

After

<GeneralCompliance>File size is less than expected size (actual 8585, expected &gt;=8589, offset 0x20BD)</GeneralCompliance>

With --Output=XMLWitAttr :

<GeneralCompliance actual="8585" expected="&gt;=8589" offset="0x20BD">File size is less than expected size<GeneralCompliance>

Also add percentage of the actual file size compared to the expected file size of a better estimation of what was lost:

<GeneralCompliance actual="7820" actual_percent="99.99%" expected="7821" offset="0x1AEE">File size is less than expected size</GeneralCompliance>

File extension mismatch is now also a conformance warning instead of a basic MediaInfo field:

<GeneralCompliance actual="mp3" expected="act at9 wav">File name extension is not expected for this file format</GeneralCompliance>