Log basic information about Riemann on startup
Improved exception handling

sys.excepthook is used to ensure we can log a full traceback, as well as
our own log message (which is necessary so that exceptions are
timestamped)
Added process:%:uptime metric
Set command line defaults correctly
Release version 1.8.0

- Set command line defaults correctly
- Added process:%:uptime metric
- Improved exception handling
- Log basic information about Riemann on startup