[patch] We can see tables in Greenplum!

Hello Hackers!

We've a fix for displaying table nodes when connected to Greenplum. The
salient bit was leaving off tgisinternal from the default template (but
leaving the template used for postgres 9.1+ unchanged).
We also added a Database helper class in test_utils for setting up and
tearing down a database. It can be used via python's with (see
TestTablesNode).

This isn't super important, but does anyone know why our test comment
doesn't show up in test output?

We see:

> runTest
> (pgadmin.browser.server_groups.servers.databases.schemas.tables.templates.table.sql.tests.test_tables_node.TestTablesNode)
> ... {'oid': 106072, 'has_enable_triggers': '0', 'name': 'test_table',
> 'triggercount': '0'}

Whereas for other tests we see output like

> This function update the server details (Default Server Node url)

Cheers!
Tira & George