download a file from the server before the server is considered fine to use
for the given test case. This should fix the cases where the server can run
but curl cannot work with it.

why sometimes the control connection dies after a RETR has been sent

start... Anyway, fork() + exec() makes _two_ pids (in perl) that we need to
track and kill after use. Thankyouverymuch.

Made the ftp server use the passed in pidfile name, and made runtests.pl
pass it in properly.

a pidfile for the server appears as otherwise it failed.

this happens for some ipv6-enabled hosts on which sockfilt cannot listen
on ipv6.

and sockfilt.c. For good-to-have functions for the servers written in C.

the runtests.pl to check this differently on operating systems that
differentiate on this.

quotes around the contents

and fixed the textmode attribute thing for windows a bit

killslaves function

sometimes the server can start but curl cannot speak to it, and then we must
remember the server (in order to kill it properly) anyway.

Also, make sure to kill all servers on exit everywhere.

(problem identified by Dan F)
2. initial text mode fix for file checks, to allow better text file testing
on windows (with regard to line endings)
3. fixed to use the proper ftpserver pidfile to find pid