Just uploaded Material Maker 0.3.
Please don't hesitate to test it and send feedback (bug reports, ideas for next release, or nice textures you created with this software).

Here's what changed since 0.2:

• Added a small user manual
• Added the following nodes:
  • Combine: combines 3 greyscale inputs into a color output
  • Decompose: decomposes a color input into 3 greyscale outputs
  • Emboss: generate a lighting effect from an input image (light direction can be configured)
  • Export: defines a custom output image file when exporting
  • Noise: just random black and white pixels
• Added new patterns to the Bricks node
• Rewrote the Blur node: now can be applied horizontally, vertically or both
• Updated the Transform node so its transform can be affected per pixel with greyscale inputs (one per transform parameter)
• Added cut/copy/paste operations
• Added "C" shortcut to center the view
• Library items can now be groups of interconnected nodes

Edit: Uploaded a new release that mitigates an annoying problem where the mouse cursor is captured during a drag'n'drop operation.