Add splash screen elements

Add a table at the top of the document that holds the logo for emperor
in it. This table is hidden once the metadata-mapping file and
coordinates javascript objects are loaded.

Fixes #33
Add favicon to index.html

Logos are of course original creations of @meganap
Merge pull request #77 from ElDeveloper/issue_33

As the code works well and the build was successful I'm going to merge the PR.