OS dependent features and general utilities in PHCv2.3.07

New in the second release is the inclusion of test programs (prefix "ts_").
A timer interfacing with C was needed for the Windows platform and Itanium
machines, moved in release 2.3 to a separate subdirectory Basic_Timer.
The unix timing facilities were moved to the subdirectory Unix_Timer.
An extra procedure was added to communications_with_user in release 2.3.

------------------------------------------------------------------------------
file name                 : short description
------------------------------------------------------------------------------
natural_io                : instantiation of text_io with natural
integer_io                : instantiation of text_io with integer
time_stamps               : date, time, and elapsed time
system_call               : allows to execute UNIX system commands
machines                  : specific system calls
unix_command_line         : handling arguments on the command line
bye_bye_message           : message at the end of the program
communications_with_user  : dialogue to manipulate files, choose options
file_scanning             : scanning a file for text banners
------------------------------------------------------------------------------
ts_stamps                 : test on date, time, and elapsed time
ts_ctimer                 : timing with a call to ANSI C
ts_syscall                : execution of a system call : "ls"
ts_mach                   : prints system information of current process
ts_cmdline                : prints the arguments of the command line
ts_byemess                : prints the message at the end of the program
ts_commuser               : tests the dialogues with the user
ts_filescan               : reads a file name and banner, and scans for it
------------------------------------------------------------------------------

A package like Unix_Command_Line is available in some form in most Ada
compiling systems.  For encapsulation purposes it is included here.

The file scanning operations are part of the database management of the
system input files to PHC.
