some tests failing under sqlite3

[istruble]

There are a few tests that are failing due either to syntax quirks or functionality differences in sqlite3.

In sqlite3 land, now() is not supported but you can use {date|time|datetime}('now') in its place. test_alter_column_null in test/logic.py uses now().

All stored data in sqlite3 is dynamically typed. There are also a few limitations on what ALTER TABLE can change. Tests that exercise these limitations (or quirks if you prefer), should probably be skipped for sqlite3.

Running the south tests with sqlite3 under 0.6.2 and changeset 550 both result in:

FAILED (failures=1, errors=5)

[istruble]

patch for failing tests under sqlite3

[andrew]

SQLite tests now all pass.