Logging improvements

[neilcook]

Previous to this PR, stdout would log everything, even debug logs. Additionally, the new webserver would log only errors, with no way to debug issues.

This PR:

• Adds a log level command line flag to wforce and trackalert
• Adds a global log level variable used by dolog.hh used to filter logging to stdout
• Uses the configured log level to set drogon webserver log level (which also logs to stdout - it has no syslog capability)

[neilcook]

thanks Peter!