Fix typo
SVG logo

I traced the current logo in Illustrator to get a good version. And with
SVG we don't need any 2x magic because it's already vector. I should
probably care about IE8, but I don't.
Small tweaks to HTML to JSX page:
 - Remove "Compiled JS" tab since it doesn't make sense
 - Relabelled editor to "Live HTML Editor" rather than "Live JSX Editor"
Merge pull request #2101 from jeffchan/patch-1

Fix typo in ReactDefaultPerfAnalysis comment
Merge pull request #2124 from Daniel15/htmltojsx-fixes

Small tweaks to HTML to JSX page
Merge pull request #2120 from zpao/svg-logo

[docs] SVG logo