CMR - fixes in the report printing version
remove -1 from SMS line item in invoice for enterprise plans
do not invoice subscriptions upgraded from non-enterprise to Dimagi enterprise
add disable-on-submit to exchange view
add clarifying text about languages not affecting mobile apps

http://manage.dimagi.com/default.asp?148698
Switch single select questions to be represented as one column, rather than a column for every option in the select.
extend fluffs to support product code
Merge branch 'master' into ih_product_code
refactored SQLdata models to support grouping by product_code
pull out migration-related styles into separate file so that core styles can be used in new static site
added suporting for product_code
flake8
code refactoring
Merge pull request #4931 from dimagi/ucr-single-select-normalize

Default single select questions to 1 column in data sources
Merge pull request #4930 from dimagi/do-not-invoice

do not invoice subscriptions upgraded from non-enterprise to Dimagi enterprise
Merge pull request #4928 from dimagi/invoice-1

remove -1 from SMS line item in invoice for enterprise plans
code refactoring
Merge pull request #4922 from lwyszomi/opm-images

CMR - fixes in the report printing version
Merge pull request #4933 from lwyszomi/ih_product_code

IntraHealth - changed grouping from product_name to product_code
Merge pull request #4935 from dimagi/case-148698

add clarifying text about languages not affecting mobile apps