The logger pmda now asks for a logfile to monitor.

The logger pmda now asks for a logfile to monitor.

* pcp/src/pmdas/logger/logger.h: New file.
* pcp/src/pmdas/logger/loggerMain.c: New custom main loop.
* pcp/src/pmdas/logger/logger.c (main): Added option for logfile to
  monitor and calls new custom main loop.
* pcp/src/pmdas/logger/Install: Asks for logfile name to monitor.
* pcp/src/pmdas/logger/GNUmakefile: Added loggerMain.c and logger.h.