Checks whether the files to process are collected with movisens accelerometers.
ismovisens.RdChecks whether the files in the datadir folder are files collected with movisens accelerometers. Note that movisens data are stored in one folder per recording that includes multiple bin-files (instead of one file per recording as usual in other accelerometer brands). Therefore, datadir indicates the directory where all the recording folders are stored, then, GGIR reads the pertinent bin files from every folder.