add 3.4.0 link to docs
add 3.4.0 link to docs

thomaspark/bootswatch,douglaskastle/bootswatch,douglaskastle/bootswatch,douglaskastle/bootswatch,thomaspark/bootswatch,thomaspark/bootswatch,nkraft/bootswatch,douglaskastle/bootswatch,nkraft/bootswatch,nkraft/bootswatch