zpm: organize and sort imports
zpmlib: add logger
zpmlib: replace print statements with logging

With the exception of a few cases, most of the `print` statements that
existed in the codebase were used to display debugging information. Most
of these statements have been replaced with `debug` or `info` logging
statements, where appropriate.
commands: add `with_logging` command decorator

This decorator allows for convenient addition of the `--log-level/-l`
option to a zpm command function (such as `new`, `bundle`, and
`deploy`). The inner function of the decorator also handles log level
initialization prior to the execution of the command function.
commands: add log setup to new, bundle, and deploy
tests: update cram tests with `--log-level` flag
Merge pull request #116 from larsbutler/fix-stdoutput-and-logging

Separate standard output and logging information