Server.R was modified to read in the names of Excel data sheets and use those names to populate the drop down list of data sheets the user can examine.  This replaces the hard-coded list of data sheet names that used to be in ui.R.
Server.R was modified to read in the names of Excel data sheets and use
those names to populate the drop down list of data sheets the user can
examine.  This replaces the hard-coded list of data sheet names that
used to be in ui.R.

File format error checking is still needed.

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