Hooray, version 1.1 is finally out! 

Here's a list of what's changed, hopefully I haven't missed anything!

New Features

• Added a full undo/redo system! It's finally here! Pretty much everything (except camera pans/zoom) will now have it's current and previous state stored so you can undo and redo to your hearts content. Undo/Redo can be accessed via the Edit menu, but also by Ctrl + Z and Ctrl + Y
  I understand that Mac users will be expecting Command + Z and Command + Shift + Z, and I will look into this once I have access to a mac again. I'll also be looking into customising these keys.

• Preview window has now been separated from the render tab and will popup once the rendering is complete. The save options can now be found here.
• Animations can now be saved as sprite sheets, individual images (just pick a base filename and it will append a number to the end) and also GIF! Please note that GIF export isn't very good at the moment. It works, but it's slow and the files are very unoptimised. For example, a 256 x 256 animation with 200 frames will probably take around 5-10 seconds to save and the file is around 10mb.. not great. It's fine for smaller animations though. I'll try and improve this with a better library in the future.
• Rendering can now be delayed for a certain amount of frames, this can be useful when you want to let the simulation run for a while before capturing it
• Added visual guides for the emitter shape radius/extents
• Added basic controls for playing, stopping and scrubbing through the frames of the animation in the preview panel
• Added live update to the preview panel when changing the output scale so you can see how the final scaled animation will look when exported
• Added min/max radius to circle emitter shape. Particles can now be emitter between an inner and outer circle radius
• Added radial spawn offset. Particles initial position can be offset in the direction they are spawned in, allowing you to create a ring of particles for example
• Added spread randomness. When an emitter has a spread value, the particles will normally choose a random direction within these bounds. Now you can choose how random that is. If you disable randomness completely (i.e 0) then the angle of the particles will increment as each new particle is spawned. This works well when using a burst value of 1 as all particles spawned will be equally distributed around the emitter
• Added option to align particles rotation with it's velocity. Does what it says on the tin! Particles can now point themselves in the direction they're moving. This overrides any other angle values/curves.
• Added new Symmetry effect node. This is super useful and really helps when creating more stylised looking effects. Symmetry can be enabled in both the X and Y axis

Bug Fixes

• Fixed a bug where the emitter box shape's width and height were the wrong way round
• Fixed a bug where emitter positions were reset when rendering
• Fixed issues with emitter motion (sin & cos) effecting the original base position of the emitter
• Fixed a bug where some curve data was shared between duplicated emitters. It did produce neat results though, so maybe turn it into a feature?
• Not really a bug fix, but added some text on the effects tab area so people know how to add new effect nodes.. :}

Welp, that's it for version 1.1, I hope it covers what some of you thought was missing. As always, I'm very open to suggestions for improvements and new features (when possible) so don't be afraid to let me know on in the discussion section at the bottom of the main page!

Cheers guys!