Navigation: Related field support to SourceColumn

Add support to the SourceColumn class to resolve related fields
using the double underscore as separator. Columns that use related
no longer have to use throw away lambdas.

Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>

mayan/apps/common/forms.py

@@ -11,7 +11,7 @@ from django.utils.translation import ugettext_lazy as _
 
 from .classes import Package
 from .models import UserLocaleProfile
-from .utils import return_attrib
+from .utils import resolve_attribute
 from .widgets import DisableableSelectWidget, PlainWidget, TextAreaDiv
 
 
@@ -43,7 +43,7 @@ class DetailForm(forms.ModelForm):
         super(DetailForm, self).__init__(*args, **kwargs)
 
         for extra_field in self.extra_fields:
-            result = return_attrib(self.instance, extra_field['field'])
+            result = resolve_attribute(self.instance, extra_field['field'])
             label = 'label' in extra_field and extra_field['label'] or None
             # TODO: Add others result types <=> Field types
             if isinstance(result, models.query.QuerySet):
@@ -53,7 +53,7 @@ class DetailForm(forms.ModelForm):
             else:
                 self.fields[extra_field['field']] = forms.CharField(
                     label=extra_field['label'],
-                    initial=return_attrib(
+                    initial=resolve_attribute(
                         self.instance,
                         extra_field['field'], None
                     ),