release devel v1.1.5 as v1.2.0
v1.3.0: ISC license, credits, new fixes

new fixes:
- http://meta.stackoverflow.com/q/143973: Images can be pushed outside
the boundaries of a post by using nested lists
- http://meta.stackoverflow.com/q/214706: The branch prediction answer
is overflowing
- extended "MathJax in suggested question titles" fix to user profile
summary pages
other changes:
- add explicit ISC-style free license
- add credit notes to fixes based on code by others
- adjust line break to (mostly) fit under 80 columns
- reorder list of fixed in README to match code