Added empty input data error catching for PCA analysis.
Added empty input data error catching for PCA analysis.

thehyve/heim-Rmodules,transmart/Rmodules,UMich-Transmart/Rmodules,UMich-Transmart/Rmodules,UMich-Neptune-Transmart/Rmodules,thehyve/Rmodules,cdejonge/Rmodules,thehyve/Rmodules_oncoprint,thehyve/Rmodules,transmart/Rmodules,thehyve/Rmodules_oncoprint,cdejonge/Rmodules,baumjamin/Rmodules,UMich-Neptune-Transmart/Rmodules,thehyve/heim-Rmodules,baumjamin/Rmodules,UMich-Transmart/Rmodules,UMich-Neptune-Transmart/Rmodules,thehyve/heim-Rmodules,baumjamin/Rmodules,transmart/Rmodules,wimvanderlinden/Rmodules,thehyve/Rmodules_oncoprint,baumjamin/Rmodules,UMich-Neptune-Transmart/Rmodules,cdejonge/Rmodules,cdejonge/Rmodules,UMich-Transmart/Rmodules,wimvanderlinden/Rmodules,thehyve/Rmodules,wimvanderlinden/Rmodules,thehyve/Rmodules,transmart/Rmodules,thehyve/heim-Rmodules,wimvanderlinden/Rmodules