Merge pull request #34 from cihub/master

Dev upmerge after accepting PR
'Max rolls' feature for 'date' rolling logger. #35.
A few changes to the new rolling logic. #35.
Fixed new rolling writer tests. #35.
New roller: minor fix+comments. #35.
Rolling writer: fixed rename issue on windows. #35.
Merge pull request #35 from cihub/gs_issue_35

Max roll attribute for "date" type.