timezone of starttime_posix doesn't matter

starttime_posix later gets converted with as.numeric(), which produces a Unix timestamp, which is always in UTC.  So converting starttime_posix from configtz timezone to desiredtz doesn't achieve anything. The only thing that matters is that we use the correct timezone when converting from the original string representation to the POSIX object.

This extra operation wasn't breaking anything, but I think it's better to remove it so that there isn't any illusion from reading the code that the returned timestamps are somehow in desiredtz. They are unix timestamps, in UTC.

R/readGENEActiv.R

@@ -65,8 +65,6 @@ readGENEActiv = function(filename, start = 0, end = 0, progress_bar = FALSE,
   } else {
     starttime_posix = as.POSIXlt(starttime, tz = configtz,
                                  format = "%Y-%m-%d %H:%M:%OS", origin = "1970-01-01")
-    starttime_posix = as.POSIXlt(as.numeric(starttime_posix),
-                                 tz = desiredtz, origin = "1970-01-01")
   }
 
   # Correct timestamps