C. elegans data sample for Pergola documentation

C. elegans data sample for Pergola documentation (http://cbcrg.github.io/pergola/quick_start.html). The sample data set consists in two folders: One named "worm_speeds" containing a CSV file for each of the tracked worms. From the several measures that can be found in the individual files, in this example we will use mid-body speed. The "mapping" folder contains the "worm_speed2pergola.txt", which sets the mappings between the information represented in the worm_speed files and the pergola ontology.