Added the ability to load data in WFDB (WaveForm DataBase) format
plot.empi() function was added.
plot.ecg() function was added.
read.ecg.signals() function was added.
Extended examples added to the package-level documentation.
The read.csv.files() function also supports files where the channel names are given in the second line.
The read.empi.db.file() and empi.execute() functions now return object of class empi.
Fixed a bug in the empi2tf() function that caused TF maps to be displayed incorrectly for channels other than the first one (only applies to signals with more than one channel).
clear.cache() function. Before deleting files from the cache, it displays a list of them and asks the user for permission to delete them.
empi.execute() function. Additional validation has been added to ensure that list items have the required names (signal and sampling.rate).
empi.install() function. Added error handling for download.file() function.