Add support for passing arguments to the OCR backend.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/ocr/settings.py

@@ -18,6 +18,10 @@ setting_ocr_backend = namespace.add_setting(
     global_name='OCR_BACKEND', default='ocr.backends.pyocr.PyOCR',
     help_text=_('Full path to the backend to be used to do OCR.')
 )
+setting_ocr_backend_arguments = namespace.add_setting(
+    global_name='OCR_BACKEND__ARGUMENTS',
+    default=''
+)
 setting_auto_ocr = namespace.add_setting(
     global_name='OCR_AUTO_OCR', default=True,
     help_text=_(