Add gitignore file.
Support for django 1.4 alpha.

* Added _DJANGO_VERSION to the DatabaseWrapper so it'd be available in the
  various Database* objects
* Check if _DJANGO_VERSION >= 14 when calling DatabaseOperations superclass
  init method to be compatible with django 1.4
* Guard against settings.DATABASE_OPTIONS not existing
Deal with bulk_insert related changes.
Make it backwards compatible.
Fixed bug in regards to bulk inserting.
Fix bug when inserting with a specific primary key.
Use SCOPE_IDENTITY in INSERT queries to get the inserted id.
Fix bug when generating insert queries on django < 1.4.

Closes #1 #2
Support for BigIntegerField / bigint.
Apply elver@bfd353b9edb407c7829
Merge branch 'django-1.4' of https://github.com/elver/django-pyodbc into django-1.4
Merge branch 'django-1.4'

Conflicts:
	.gitignore