move LazyEncoder into hqwebapp
cleanup of some invoice pdf things for vocab and reducing ambiguity
fix error on invoice creations when there is no end_date
get pdf data for invoice
check if non hidden invoices exist for domain
add view to download pdf invoice
finish billing statements view
prepend pdf filename with invoice id
send invoice email as html and plaintext with the pdf attachment
invoice no is statement no
remove print statement
Merge pull request #2897 from dimagi/billing-statements-view

Billing statements view and Invoice email