Broken links in the source code

[mosc9575]

There is a typo for the iris data set, at the end a t is missing

bokeh_sampledata/src/bokeh_sampledata/iris.py

Line 25 in cbf9d18

.. _Fisher's Iris dataset: https://en.wikipedia.org/wiki/Iris_flower_data_se

• wrong link to https://openflights.org/data.html does not exist anymore

bokeh_sampledata/src/bokeh_sampledata/airport_routes.py

Line 11 in cbf9d18

Sourced from https://openflights.org/data.html on September 07, 2017.

• link to http://services.nationalmap.gov does not exist anymore

bokeh_sampledata/src/bokeh_sampledata/airports.py

Line 11 in cbf9d18

Sourced from USGS service http://services.nationalmap.gov on October 15, 2015.