Created less-templated base for FeatureGroup and moved its
implementation into *.hpp file, allowing to remove <algorithm> header
from FeatureGroup.h (and meanwhile removing forgotten one also from
AbstractGroupedFeature.h). Saved another ~10 seconds of compilation time
(previously ~4:21, now ~4:11).
Removed workarounds for alias templates, variadic templates and
anonymous enums, but 1.8.2 has some bug with forward declarations
causing classes to appear in default namespace, breaking
cross-references.
Allows to animate objects, pause, repeat and resume the animations. The
user implements animation step and can perform actions on state changes.
Each Animable is part of some group which is optimized for case when no
animation is running, thus it is possible to create multiple independent
"animation islands" to improve performance.
Using header with forward declarations, containing declarations for all
classes with default parameters. The classes themselves don't have the
defaults.
This also allows users to more conveniently forward-declare instead of
digging in sources and writing the declarations on their own.