Update minimum date

ESD is available for almost all data
Update data retrieval style and dataset selection

Data preview (table view) now overflows the container.
Makes it clearer to users that there are more columns.
Rename Choice 1/2 to Select, not perfect.. but better, it takes less
space
Disable/enable weather/event selectors

The selectors will be enabled or disabled when a station is selected.
Request from API if selected station has weather/event data.
Update API url processing, prevent multiple trailing slashes.
Enable axislabels on canvas for labels on 'Save Image'
Add comment to 'obsolete' css
Make separate weather and event station lists

First select datatype, then select a station from the filtered station
list.
Less API requests than previous solution.
Easier to find stations with some weather
Add retina logos
Fix retina header image

background-size needs to be set for each style
Merge branch 'master' into fitting