v0.5.6

• SAMPLE_CLASS=PDX or SAMPLE_CLASS=Xenograft now both display mouse
  icons on patient view (#786)
• Disable overlapping studies warning
  (#787)
• pathology report sometimes showing up even if it doesn't exist on
  patient view (#791)
• only pathology report check on patient view if it is a TCGA study
  (cbioportal/cbioportal-fronted#812)
• disable timeline axis trimming on patient view when browser is zoomed
  (#818)