Release Name: 0.6.0

Notes:



Changes:
## 0.6.0

- Compatibility with DBI 0.4.0 ensured.
- Support for multi-column primary keys added.
- MySQL support improved and spec'ed.
- SQLite support improved and spec'ed.
- MIT licence adopted.

## 0.5.5

- Improved and added numerous specs.
- More precise NoMethodError? thrown on Model instances. (r2601)
- DBI::Timestamp now behaves like Time. (r2602)
- Model instance writers now properly modify object values (not just database).
- nil values in condition clauses ([] and "where") no longer generate wrong SQL.