Ensure separate rows for billing statement items with different costs
Maintain an ordering when querying statement line items in tests
Remove stray print
Juggle unicode and bytes in jsbox logging.
Restore test that got deleted accidentally.
Merge branch 'feature/issue-995-fix-jsbox-unicode-logging' into develop
Add session costs to billing statements
Fix failing statement task test
Update calls to request json() data to match new requests.
Update MockRpc to new requests json.
Merge branch 'feature/issue-1072-fix-requests-json-usage' into develop
Allow LineItem credits field to be null
Update LineItem model fields to not use '' as a default
Update billing statement tasks to include account fee
Fix billing statement view tests after adding account fee
Update the context given to billing statement template to use 'sections' instead of 'channels'
Ensure vumi is the last biller displayed on statements
Handle Nones in billing statement template
Add pip freeze to Travis builds.
Switch to 'pip list' since it's sorted, more nicely formatted, and notes which packages are installed via -e) (tx @jerith).