pluralization update

[jameswinegar]

In commit 90f506a, there was a change in the name standardization of URLs and instead of using verbose_name_plural, the library uses model_name. This leads to some annoyances with multiple word models such as EntityAttrbiute having a URL of entityattribute instead of entity_attribute.

A PR could be done to use verbose_name_plural if it exists with a change to _meta.verbose_name_plural.replace(" ","_").lower(). The replacement would be required because inflector operates on the last word in the string and doesn't normalize the spaces.

from inflector import Inflector
from django.utils.module_loading import import_string

inflector_language = import_string("inflector.English")
inflector = Inflector(inflector_language)
print(inflector.pluralize("Two Word").lower())
print(inflector.pluralize("Two_Word").lower())

two words
two_words