More logging in verbose mode

I ran into an obscure stack trace (i.e. Yaml can't use utf-8 to decode some result) when I supplied my topology with a wrong python module. So I have to modify the original pyleus source code to narrow down which entry was giving me trouble. This PR will allow one to turn on verbose option and supply useful debug output.

* Set log level to DEBUG if verbose option is ON
* Sprinkle debug log before executing module for full topology

Example output:

DEBUG:pyleus.cli.build:Assemble component module: access_log_topology.s3_file_spout
DEBUG:pyleus.cli.build:Assemble component module: access_log_topology.access_log_bolt
Would you mind calling it `log`? We use that name elsewhere in the project and I'd like to keep naming as consistent as possible. Not a big issue, by the way.

Fix and +1