Antimony 0.9.1
--------------

### News:
This release adds support for nested graphs!

The UI is also rewritten, pretty much from scratch.  It implements the same
functionality in fewer lines of code and should be more robust in keeping the
graph and UI synched.

## Nested Graphs
You can now add a subgraph by selecting `Graph` from the `Add` menu.

In its parent graph, a subgraph looks just like a script node:

![Subgraph from parent](/doc/imgs/sub_outside.png?raw=true)

The three icons open up
- The subgraph (as an editable graph)
- A single 3D viewport showing the subgraph
- A set of four 3D viewports showing the subgraph

Within the subgraph, you can add Inputs and Outputs from the `Add` menu.
These inputs and outputs are strongly typed and show up as floating Datums:

![Subgraph from parent](/doc/imgs/sub_inside.png?raw=true)

--------------------------------------------------------------------------------

### Other features:
- Unified undo / redo framework (should be more robust)
- Drag / drop targets are now larger (thanks, @awgrover)
- Local datum looking with `self` (thanks, @awgrover)

### Bugfixes:
- Trying to export at resolution 0 now prints an error message
- Fixed an edge case where undoing a connection didn't restore original text
- Fixed transparent windows on Wayland (thanks, @ApostolosB)
- Parsing long expressions doesn't fail
- Fixed `QGestureManager` crash (thanks, Qt 5.5)
