content revisions; use uri- prefix for uri attributes
fix broken examples in README
change pre.highlight class prefix to .pygments
drop type attribute on script element for MathJax
use source highlighter name consistently before highlight class on pre element
output attribution in front of citetitle in quote & verse blocks
update default stylesheets

- clean up abstract block styles
- darken lead paragraph color
- increase line-height on block title, decrease margin
- update & shrink CodeRay styles
- drop generic font-family names
- style quote blocks like quote blocks
- style verse blocks like verse blocks
- lighten table header background color
- make toc title responsive
- properly align floating section anchor
- add background color on listing blocks when not added by highlighter theme
- reduce size, reposition of floating language text in listingblock
- increase size of conum
- tweak letter and word spacings
- don't use color on qanda question text
- add background color to exampleblock
- darken listingblock color in sidebarblock
- fix appearance of listingblock in print styles
don't parse link attributes if text doesn't contain = sign
set version to 1.5.0.rc.6 [ci skip]
Release 1.5.0.rc.6
prepare for next development iteration [ci skip]
enable feature tests in Travis CI
guard against nil times in timings.rb
fix invalid character class in regular expression
add compat tests for backticks (relates to #718)
fix heading level in README
tweak responstive font size for code blocks
update project description
add test for double quotes around monospaced phrase
add font @import statement inside comment to default stylesheet