Refactored main code file.  Logic for plotting raw data and trend tests has been moved to new external files Plot_Raw_Data.R and Plot_Trend_Tests.R.
Refactored main code file.  Logic for plotting raw data and trend tests
has been moved to new external files Plot_Raw_Data.R and
Plot_Trend_Tests.R.

Also added a tabular display for data files and trend tests, and
removed the functionality for opening a new file from the code for
displaying data to a separate reactive data item.

LanceFiondella/srt.core,LanceFiondella/srt.core,arhik/srt.core,LanceFiondella/srt.core,arhik/srt.core,LanceFiondella/srt.core,LanceFiondella/srt.core,arhik/srt.core,arhik/srt.core,LanceFiondella/srt.core