Update README.markdown

Fix #1426

Fix typos and improve grammar, phrasing, and terminology; reduce superfluity
Merge pull request #1448 from emth/readme

Update README.markdown
Add support for Slovenian in PDF2 #1449
Update test suite
Improve and fix Attributes builder
Add initial image metadata implementation #1453
Change image dimension reading in XHTML #1453

Remove Java extension for ImgUtils and use ImageMetadataModule instead.
Remove resource-only files from image metadata processing #1453
Remove deprecated argument properties #1455

* args.odt.include.rellinks
* args.fo.include.rellinks
* disableRelatedLinks
Fix ODT link processing bug #1455