Updated logo

Updated logo to match new F# Software Foundation logo for F#.  See
composition guidelines for logos at
http://fsharp.org/foundation/logo.html for details
Merge pull request #694 from ReedCopsey/master

Updated logo
Html Fixes

* Make sure all toLower/toUpper are using invariant
* Add missing toLower calls and remove extra not needed toLower calls
* Small tweaks to docstrings
* Replace br's with newline in InnerText
* Fix for #703