Typedal

Fix

* Py4web-specific DAL now provides a singleton per db_uid, so different apps using shared typedal classes share a db instance, leading to less weird behavior (e.g. on `db.commit()`) ([`a2af3d5`](https://github.com/trialandsuccess/TypeDAL/commit/a2af3d52a3f14ddddd40ec326df9c2705ef26eca))

Fix

* Bool(QueryBuilder) should NOT look at the data but if any filters were applied ([`962ddf3`](https://github.com/trialandsuccess/TypeDAL/commit/962ddf37f5d1ac014b73fd6349099100cc7efb5f))

Feature

* Add `condition_and` to .join so you can add additional requirements to inner joins ([`0ae688b`](https://github.com/trialandsuccess/TypeDAL/commit/0ae688ba01f421c70a660b5bb5d9672484494aa4))

Fix

* Use right 'timestamp' field ([`2aedb02`](https://github.com/trialandsuccess/TypeDAL/commit/2aedb027b4490f8284253e9c7f427b0660b6bc13))
* Allow specifying a field to Builder.count(...); support selecting extra fields (e.g. MyField.count()) ([`ce28a79`](https://github.com/trialandsuccess/TypeDAL/commit/ce28a7995a6d817424462f8b18383c85fa349ba4))

Fix

* Paginate with limit=0 will yield all rows instead of crashing pt2 ([`78f1ae7`](https://github.com/trialandsuccess/TypeDAL/commit/78f1ae7257af0ba90040a7356ad579d3c77aa231))

Fix

* Paginate with limit=0 will yield all rows instead of crashing ([`76813e6`](https://github.com/trialandsuccess/TypeDAL/commit/76813e63fc2a0915de2ae5aa3df5be0254678f8b))