allow null for date_of_experiment field in analytics since "line" procedures do not have a date
Merge branch 'master' of https://github.com/mpi2/PhenotypeArchive

# By ckchen-ebi
# Via ckchen-ebi
* 'master' of https://github.com/mpi2/PhenotypeArchive:
  refactored output of search page download
  updated sql to get for genes/mp annotated to legacy pipeline using project_id instead of pipeline_id: ie, eumodic (id:1) is legacy, everthing else is postQc