Update version to 1.5.0-dev
Update version to 1.5.0-dev

* The last couple of changes took away Python<2.6 compatibility.
* The grid iterator is an API addition, thus semantic versioning
  requires incrementing the minor number.
* Python 3 compatibility is non-trivial enough that keeping the
  same minor number makes no sense

FormAlchemy/formalchemy,camptocamp/formalchemy,FormAlchemy/formalchemy,FormAlchemy/formalchemy,camptocamp/formalchemy,camptocamp/formalchemy,FormAlchemy/formalchemy,camptocamp/formalchemy