started library (vicare posix pid-files)
development of pid-files library
tweaking test file
updated echod demo program to use (vicare posix pid-files)
more contents for demos readme file
review of documentation for pid-files library
updated announce file
moved documentation of simple event loop library to the posix texinfo file
renamed library (vicare simple-event-loop) to (vicare posix simple-event-loop)
added expiration time for file descriptor events in the simple event loop library
updated echod demo program