Fixes undefined index errors.
Added ability to mark an invoice as paid, unpaid or uncleared.
Fixes bug that unable to edit invoices from Admin Control Panel.
Fixes "Undefined index: invoice_item_id" error.
Removed currency symbols from invoice to prevent some character encoding errors.
Fixed bug that adding invoice item fields that clash with existing invoice item fields causes an error, rather than overwriting them.
Recurring invoices can now recur on a certain number of days/months/years (same as user upgrades), rather than only every 1 week/1 month/1 year.
Fixes issues with recurring invoices page on front end.
Turned off feature that recurring invoices may create a single invoice if multiple occur on same day, due to incompatibility with Infusionsoft API by Waindigo.
Various other bug fixes.
Added support for Infusionsoft API by Waindigo.
Fixed bug that all page numbers link to Invoices Splash page on Invoices list.
Fixed bug that filter doesn't work on Invoices list.
Fixed bug that adding a recurring invoice redirects to adding an invoice, so unable to add recurring invoices.
Added phrase waindigo_requested_invoice_not_found_invoices, and removed incorrect phrase and_invoicing_requested_invoice_not_found.
Fixed character encoding in PDFs to avoid "Detected an illegal character in input string" on some servers and/or strange characters being output.
Fixed bug that 'void' invoices are not clearly visible from ACP. Invoices are now permanently deleted instead for now.
Fixed bug that alerts were not being created.
Included missing Zend/Memory library files needed to view PDF invoices.
Includes missing Waindigo_Pdf files required for viewing PDF invoices.