More logging in verbose mode

* Set log level to DEBUG if verbose option is ON
* Sprinkle debug log before executing module for full topology
Change logging level to WARNING if verbose is False
Don't delete system-installed base jar on build

To save space in toplogy jars, the CLI deletes the unnecessary base jar
from the virtualenv before packing it into the topology jar.

This didn't account for users using --system-site-packages, however, and
it would still attempt to delete the base jar from its system-installed
location.

Closes #74
Fixed a typo
Merge pull request #80 from msmakhlouf/develop

Fixed a typo
Minor typo fix
Merge pull request #81 from johanneshk/patch-1

Minor typo fix
Merge pull request #78 from patricklucas/dont_delete_system_base_jar

Don't delete system-installed base jar on build
Update CHANGELOG
Rename logger to log
Merge pull request #70 from smoy/smoy_debug_logging

More logging in verbose mode
v0.2.4 release