support prev/next button for multiple studies
support prev/next button for multiple studies


Former-commit-id: 54977fb1554b47b020e67baa5801aa8467cf8865
alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,alisman/cbioportal-frontend