don't load MathJax manually; remove duplicate ignoreClass entry
update default theme

- align colors on #f8f8f7
- set line of headings to 1.2
- remove excess panel styling
- fix border bottom on sidebar toc below breakpoint
- fix spacing between sections below breakpoint
- reduce padding around doctitle in print styles
- add box shadow to example block
- remove background and padding around code in table cell
- add output style class for literal block
- adjust indentation of header meta