station and component are assumed to be the last elements
of a file name - this function returns a list with these text strings.
Usage
parseFN2STA(fn, ista, icomp, sep="\\." )
Arguments
fn
text file name
ista
index of station name counting from the end of the file name
icomp
index of station name counting from the end of the file name
sep
seperator token in file name
Value
list(sta='text station name', comp='compname')
Details
Some format store the station in the file name
rather than the seismic header.
Default assumes that the station name and the component name
are the last items on the file name seperated by a period.
So ista and icomp are computed from the end of the file name,
i.e. ista=1 and icomp=0.