Add new hpaVis functions for RNA datasets

[anhtr]

HPA has recently provided RNA data for single cell types, blood and brain. These data are visualized on HPA website for each single genes. For example: https://www.proteinatlas.org/ENSG00000168757-TSPY2/celltype. I would like to create similar visualizations, as far as the downloadable datasets allows, which let user see multiple genes in one plot.