Add museum catalogue data

* inst/extdata/NMSI_100.csv: Add the 100 first rows of the museum
  catalogue data released under the Creative Commons
  Attribution-NonCommercial-ShareAlike license
  (http://creativecommons.org/licenses/by-nc-sa/3.0/)
  by the Science Museum in London, UK.
  (http://api.sciencemuseum.org.uk/documentation/collections/)