Remove trailing whitespace
Remove unused imports
Reorder imports
Fix whitespace

Add whitespace after comma, remove whitespace around equal sign for
default parameters
Use single quotes for strings
Add line breaks to long lines
Conver unassigned list comprehensions to loops
Add missing docstrings

Also use ordering constant from QuerySet class
Avoid short variable names
Define all attributes in __init__ method
Undo import change that was there for testing
Avoid using lambda when not needed
Merge pull request #46 from jcollado/blitzdb-backends-file-index-cleanup

Blitzdb backends file index cleanup