Add doctest to with_metaclass()
Remove deprecated Real class and is_Real property of Basic, see issue 1721
Remove deprecated 'each_char' option for symbols(), see issue 1919
Merge pull request #2391 from asmeurer/with_metaclass_doc

Add doctest to with_metaclass()
Merge pull request #2313 from skirpichev/deprecated-0.7.0

Remove some stuff, deprecated since 0.7.0
Merge branch 'master' into 3741-nargs-as-tuple
Drop nargs specifications from Lambda-derived classes