minor readme reword
fix sqlalchemy regression
fixed reference to wrong XmlDocument location
fixed according to documentation
Merge pull request #215 from emeusel/master

Small documentation fixes
don't propagate non-nullable in subclass attributes.
remove needless call of gen_sqla_info() in sqla tests.
add default ctor tests, add support for default values.
minor.
also accomodate non-abstract mixins as bases
versioning update.
Nullify known attrs while making sure not to conceal user errors.
Update typo in comment and update .gitignore
Merge pull request #217 from mjzshd/master

fix typo and update .gitignore
Merge remote-tracking branch 'arskom/master'

Conflicts:
	.gitignore
minor
fix a final quirk in complex object ctor.
close contexts on error as well.
fix timezone decisions and improve docs in DateTime
don't log iterables otherwise the logger consumes the data.