[misc] Warn that Maven 3.0.x is needed in the README
[misc] Warn that Maven 3.0.x is needed in the README

mjshepherd/phenotips,phenotips/phenotips,tmarathe/phenotips,itaiGershtansky/phenotips,tmarathe/phenotips,teyden/phenotips,JKereliuk/phenotips,veronikaslc/phenotips,alexhenrie/phenotips,JKereliuk/phenotips,teyden/phenotips,teyden/phenotips,phenotips/phenotips,danielpgross/phenotips,DeanWay/phenotips,alexhenrie/phenotips,teyden/phenotips,teyden/phenotips,phenotips/phenotips,mjshepherd/phenotips,veronikaslc/phenotips,danielpgross/phenotips,DeanWay/phenotips,mjshepherd/phenotips,JKereliuk/phenotips,danielpgross/phenotips,phenotips/phenotips,veronikaslc/phenotips,alexhenrie/phenotips,DeanWay/phenotips,itaiGershtansky/phenotips,phenotips/phenotips,itaiGershtansky/phenotips,tmarathe/phenotips