Added views for part and part category

- Worked out simple linking
- Category path displaying correctly
- Category page lists parts in category

InvenTree/part/urls.py

@@ -3,5 +3,10 @@ from django.conf.urls import url
 from . import views
 
 urlpatterns = [
+    # Display part detail
+    url(r'^(?P<part_id>[0-9]+)/$', views.partdetail, name='detail'),
+    
+    # Display a part category
+    url(r'^category/(?P<category_id>[0-9]+)/$', views.category, name='category'),
     url(r'^$', views.index, name='index')
 ]