Changes since 1.4.0:
Added HTML_SMARTYPANTS_QUOTES_NBSP, which allows having nonbreakable spaces
inside « French guillemets » (Issue #378)
Added EXTENSION_JOIN_LINES, which joins newline-separated lines into a
single paragraph. Useful for Chinese text.
Implemented support for CDATA section (Issue #165)
Fixed links with parentheses (Issue #116)
Fixed fenced code blocks inside lists (Issue #228)
Fixed regression, panic in reference links (Issues #172 and #173)
Fixed adjacent list merging (Issue #235)
Fixed definition lists that contain other lists (Issue #263)
Fixed fenced code pre-processing (Issue #279)
Fixed panic with recursive footnotes (Issue #241)
Removed rel="footnote", which is no longer valid.
