Clearing selected species on home view don't disable the statistics button

When clearing the selected species on the home view, the "Inspect species statistics" button should be disabled again, but it is not the case. Fixing this would also be a good opportunity to rework the design of the home view:

• Moving the "Clear" button in a less attractive area and make it more discreet place so it doesn't get mixed up with a "Confirm" button
• Making the button cleaner, bigger font, clearer text, larger corner radius
• Changing logo ?
• Maybe remove the search bar while it is not implemented

Moved to the more appropriate issue #27 (closed)