Pyecoregen

Fixed
- Multiple useless `EClass` and `EReference` imports.
- Opposite derived `EReference` name.

Added

- Added generation of "many" derived `EStructuralFeature` as `EDerivedCollection`.
- Added support for non unique collections of `EAttribute`.

Fixed
- Missing generation of "single" derived `EReference`.
- Keyword handling for metaclasses.

Removed
- Removed support for Python 3.4.

Added

- Added option to auto-generate the Python code for the metamodel's dependencies,
see the `--with-dependencies` option.

Fixed
- Missing imports to `EDataType` references that are contained in a metamodel dependency.
- Missing default value generation for `EAttribute`.
- Missing `eSubpackages` and `eSuperPackages` at module level.

Removed
- Removed support for Python 3.3.

Fixed

- Missing 'templates' in the sdist package. The sdist package (`.tar.gz`) is
built using information of the `MANIFEST.in` for non-source files. The
templates were simply missing in it.

Fixed

- README

Added

- Added option to auto-register generated package in global registry, see the
`--auto-register-package` option.
- Added option to specify a user module, from where mixin classes. These mixins must then implement
all end-user specific code like operations and derived attributes. See the `--user-module`
command line option.

Fixed

- EDatatype registration.
- Various derived attribute fixes.