Update description and logo of the DiffSharp library.
Fix link for F# mode for Emacs
Add HTML Type provider to F# Data type providers list
Merge pull request #349 from gbaydin/gh-pages

Update description and logo of the DiffSharp library.
Merge pull request #351 from alfonsogarciacaro/gh-pages

Fix link for F# mode for Emacs in Cross-Platform guide
Merge pull request #352 from ovatsus/gh-pages

Add HTML Type provider to F# Data type providers list
Massive logo update on "F# Community Projects" page