Include Content-Type header in all responses
Explicitly ask for application/json responses where we expect them
Add getInvoiceReport function
Add getQueuedItemLines and queueItemLine
Add tool to quickly store a lot of invoices to pdf
Add tool to generate an invoice report
bin/ui: verduidelijking contracttype bij portering
Merge pull request #1 from mrngm/master

Verduidelijking contracttype bij porteren
Handle 204 No Content response from invoice generation. Document return values from generateInvoice().
Make invoice generation less verbose. Give a warning if the PDF couldn't be generated.
Add mergeAccount() function for new external/real account merging functionality in CServ
Add support for external stub accounts, their CServ suggestions and merging them with real accounts to the NCurses UI
Add support for updating the exemptFromCostContribution boolean