Several improvements:
 1. Support any connect string by templating it.  {{username}}
    and {{password}} will be replaced by the real username/pw.
    The current max size of the connect string specified on
    the command line is 8192 characters.  Open issue or send
    pull request if you need something bigger.  This could be
    changed to dynamically figure it out.

 2. Remove -H,--host and -P,--port options.  No longer needed
    because of template.

 3. Changed -c,--connectdata to -c,--connectstring. Normally
    I wouldn't break backwards compat, but safe_sqlplus is
    only a day old, so I doubt this will break anything.

 3. Fix waitpid() issue (needed WIFEXITED() to determine if
    child exited cleanly).

 4. Added support for logging entire sqlplus session to
    ./sqlplus_session.log if using the -d,--debug flag.
    Useful if you get a connect or TNS resolve error and
    need to see exactly what the program sent to sqlplus.