Added custom options module for printers by report

corrections for travis tests

fix for flake8 errors and travis tests

added new sections and rapleced maintainers

added USAGE section in readme + bug corection for update of printers

changed copyrights

updated manifest and fix for case of false ppd

printer_custom_options/models/printer_option_choice.py

@@ -0,0 +1,33 @@
+# Copyright 2019 Compassion
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+from odoo import api, fields, models
+
+
+class PrinterOptionChoice(models.Model):
+    _name = 'printer.option.choice'
+    _description = 'Printer Option Choice'
+    _rec_name = 'composite_key'
+
+    option_key = fields.Char(required=True, readonly=True)
+    option_value = fields.Char(required=True, readonly=True)
+    composite_key = fields.Char(compute='_compute_composite_key', store=True)
+    printer_id = fields.Many2one(
+        comodel_name='printing.printer',
+        string='Printer',
+        required=True,
+        readonly=True,
+        ondelete='cascade',
+    )
+
+    @api.multi
+    @api.depends("option_key", "option_value")
+    def _compute_composite_key(self):
+        """ Composite key for a printing option key-value pair."""
+        for option in self:
+            option.composite_key = self.build_composite_key(option.option_key,
+                                                            option.option_value
+                                                            )
+
+    @api.model
+    def build_composite_key(self, option_key, option_value):
+        return option_key + ':' + option_value