Updates for new logging to appease govet

Govet doesn't like functions that look like format handlers not ending in `f`,
such as Debug() vs Debugf(). This is changing some of the new log handling to
use 'f' function names to appease govet.

Updated the implicit handling of including the client as an arg without being
used in a format string. Now the client object simply has a Errorf function
for logging errors and it adds itself onto the format string.
Merge pull request #59 from apcera/log-vet-fixes

Updates for new logging to appease govet