Saves IntensityTier to file (in UTF-8 encoding).
it is list with at least $t and $i vectors (of the same length).
If there are no $tmin and $tmax values, there are
set as min and max of $t vector.
Usage
it.write(it, fileNameIntensityTier, format = "short")
Arguments
it
IntensityTier object
fileNameIntensityTier
file name to be created
format
Output file format ("short" (short text format - default), "text" (a.k.a. full text format))