Improve inline HTML element detection.

- allow element names in any case
- allow optional / at end of closing br or hr tags
Allow detection of raw img elements.

- add img to void elements so <img ... /> is now detected
- under xhtml hr, br & img can be closed using the <hr></hr> style so we now detect this
Better test case title and notes
Add case insensitive p breaks
Update changelog
Update test note
Merge branch 'case-insensitive-html'

Relaxes hasRawText() and fPBr() rules to allow HTML5 tags to be detected in the input stream and output.
Also expands the range of tags and closing styles detected.