transfrred rtl-support changes to default, version --> 3.1.13
README.txt: slight improvements and corrections
README.txt: more corrections
paraparser.py: force assertion of tag rather than value checking in end_<tag>
paragraph.py, textobject.py: improved support for rtl, bump version to 3.1.14
added test that badly formed markup raises errors
ttfonts.py: fix reading font names in py3; contributed by masayuko @ bitbucket