Refactor and simplify session loading.   Finished load-from-parameter.
Refactor and simplify session loading.   Finished load-from-parameter.

NabaviLab/CNV-Visualizer,NabaviLab/CNV-Visualizer,NabaviLab/CNV-Visualizer,NabaviLab/CNV-Visualizer,NabaviLab/CNV-Visualizer,igvteam/igv.js,igvteam/igv.js