Create index.html

Add top-level gh-page
Adding initial html and js files.
Relative urls for js files.
Add some README text.
Fixing html layout, disable/enable controls instead of show/hide.
Adding min/max key frame distance options + scroll control.
Fixing copy behaviour, span -> p.
Adding cycle functions.
Adding --lag-in-frames option.
Input updates on bitrate field.
Adding 'output' section.
Adding 'input' section.
Two column layout.
Adding generic keyboard up/down support.
Adding 'limit' and 'skip' options.
Adding --undershoot-pct and --overshoot-pct options.
Adding --frame-parallel option
Better layout for 'Quantization' section.
Better layout for 'Bitrate' section.
Adding STDIN as input type.