slick/slick — pull request #795 by tminglei (2014-05-04 05:56:07+00:00)
Title: add pg inherits support

This patch is adding `postgres` inherits support to `slick`.

A usage example of window function is as below:
```scala
salary.avg :: Over.partitionBy(dept).orderBy(dept,salary)
.rowsFrame(RowCursor.UnboundPreceding, RowCursor.CurrentRow)
```

Can you help review and give your suggestions?