Fixed #7285: Improved inspectdb handling of dashes in table and field names....

Fixed #7285: Improved inspectdb handling of dashes in table and field names. Thanks to redalastor@gmail.com for the report and Justin Bronn for the first part of a fix.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8404 bcc190cf-cafb-0310-a4f2-bffc1f526a37