SQL optimization, avoid query in pre_save_polymorphic()

This query is visible in the django-debug-toolbar POST redirect page
Small admin documentation fix.
Include templates in install.
remove trailing '/'
Merge pull request #14 from thenewguy/master

remove trailing slash
Merge branch 'install-admin-templates' of https://github.com/onepercentclub/django_polymorphic into onepercentclub-install-admin-templates

Conflicts:
	MANIFEST.in
Merge pull request #12 from vdboor/master

Avoid SQL query in pre_save_polymorphic()
Bumped setup.py version, Changes, for 0.3 release
Merge branch 'master' of github.com:chrisglass/django_polymorphic
Point release fixes a merge error.
Remove unused load statements in add_type_form.html

This addresses Django 1.5 compatibility as well (see #16)
Merge pull request #21 from vdboor/master

 Remove unused load statements in add_type_form.html
Add tox configuration file.

Note: The tests do not currently pass.
Update DB settings for Django >= 1.4.
Import settings in tests from django.conf.
Update db_type method for Django >= 1.4 DB settings format.
Fixed the default manager test failures.

According to the django docs (1.4 / 1.5), the default manager for subclasses of
PolymorphicModel should be PolymorphicManager:

3. The default manager on a class is either the first manager declared on the
   class, if that exists, or the default manager of the first abstract base
   class in the parent hierarchy, if that exists. If no default manager is
   explicitly declared, Django’s normal default manager is used.

https://docs.djangoproject.com/en/1.4/topics/db/managers/#custom-managers-and-model-inheritance
https://docs.djangoproject.com/en/1.5/topics/db/managers/#custom-managers-and-model-inheritance
Merge pull request #20 from onepercentclub/add-tox-config

Add tox config
Added Ben to AUTHORS. Thanks a lot!
Add travis config.