It is invalid to issue a SIZE command once a data transfer is
in progress. For reads we issue the SIZE command before the RETR
command and get a snapshot of the file size. For writes the file size
is initialized to zero and incremented for each write chunk.
Script does what is expected and tries to do it as
smartly as possible.
+ remove occurrences of two blank comment lines
next to each other after Id string line removed.
+ remove entire comment blocks which only exited to
contain CVS Ids
+ If the processing left a blank line at the top of
a file, it was removed.