updated data, site buttons misc

fixes https://github.com/GraphAlchemist/Alchemy/issues/158
fixes https://github.com/GraphAlchemist/Alchemy/issues/159
renames assets to images as per https://github.com/GraphAlchemist/Alchemy/issues/145

adds href="https://github.com/GraphAlchemist/Alchemy/releases/" to all download buttons (which are now <a> elements).
(also repositions and restyles full app button)