Wireframes update

Added modals for the add form pages, also tabbed navigation for the dataset view that contains Map, Tables, Charts and Activity info
I wanted to put less focus on downloading data and also it was mentioned there's a data download history page that caches the previous downloads of data (Matt mentioned it was a technical necessity). We can either force users to go to that page first or initiate a download directly through the drop down or a less prominent text link. What do you think @mberg ? I'm not sure how (i.e. why) they would access the download history page otherwise.