Merge branch 'aggraef/purr-data-readme-update'

6 jobs for master
Status Name Job ID Coverage
  Test
canceled debian_stretch_x86_64_deb #21375
debian stretch x86_64

canceled osx_10.11_x86_64_dmg #21377
osx v10.11 dmg

canceled osx_10.8_x86_64_dmg #21378
osx v10.8 dmg

canceled raspbian_stretch_armv7l_deb #21380
raspbian arm stretch

canceled ubuntu_16.04_x86_64_deb #21376
ubuntu v16.04 x86_64

canceled windows_i386_innosetup #21379
windows i386