Log what we're executing before we execute it
Rename logfile: scalegrease.log --> 2014-07-30.log

While yes, the previous implementation did use the built in timed log
rotation, it was never triggered. The in built log rotation is meant for
long-running processes since rollver only occusr at midnight.

https://jira.spotify.net/browse/DATAEX-150
Merge pull request #18 from Tarrasch/log-rotation

Log rotation

(@sisidra approved)