add QDjangoMetaModel::createTableSql to return SQL queries

Also lowercase field types, to behave like django.
Merge branch 'master' of https://code.google.com/p/qdjango
test field creation SQL
add a comment about AUTOINCREMENT and sqlite
use QLatin1String where appropriate
QLatin1String cleanup
QLatin1String fixes
QLatin1String fixes
QLatin1String fixes
make QDjangoMetaModel::localField take a const char*
build fix
use QLatin1String where appropriate
Fix and test "unique" field option.
Make index names coincide with those used by django.
Add a "unique_together" model option.
test db_column field option
test db_table option
Do not take object ownership in QDjangoMetaModel::setForeignKey().

Fixes issue #2
reduce gratuitous new/delete in tests
add support for on_delete fk constraint