modify container and toc
move buttons to the left
top, source, bottom
buttons on hover
use media query to adapt layout based on screen size
width percentage
Merge pull request #2 from keripix/master

Used marked.js instead of showdown.js to render MD
remove non-use code, add scroller for outline
update readme and manifest.json to use markdownviewer.js
update version to 1.0.4
fix merge