Improve logging and messaging (Configurable log levels & passing useful errors back to the client)

[tammersaleh]

We're logging to two places Logger() and fmt.Printf() - are they going to the same place (stdout)? If so, why use two separate calls.

Also, many of our error messages are focused on the implementation ("Failed to initialize dohicky") instead of the impact ("Failed to connect to google.com").

• standardize logging system
• review error messages, rewriting them for the user's consumption.

[spkane]

This has been cleaned up a bit, and at the moment:

api.Logger() is used in the configureAPI() - Note: This is simply log.Printf()
log.Printf() is used elsewhere.
fmt.Print() style commands are only used in cludo client for STDOUT messages that are user facing.
CheckErr(err) is only used in cludo client for STDERR messages that result in the client exiting.

[spkane]

It would also be good to add log levels, so that message verbosity can be tuned for the audience.