* Added a "constant wave" in the pattern node
* Updated graphEdit to detect and forbid loops
* Modified code that renders to texture to update a texture instead of returning one (so we avoid updating everything and rely on everything being updated automatically wrt textures)
* base library is loaded from filesystem (instead of package) if available
* updated transform node (scale split into scale_x and scale_y, and added a repeat parameter)
* added blend modes (burn, dodge, lighten and darken)
* added a (very bad) blur node, based on generic convolution code
* rewrote normal_map node using convolution code
Updated base node class to support several outputs.
Now bricks support 2 outputs : greyscale depth map, and (random) brick color.
Now Voronoi supports 3 outputs : center distance, edge distance and cell color.
Updated bricks example to use brick color output.
Refactored rendering of textures for save and exporting material now saves all textures.
Added an option to start a clear the project, and proper "save" and "save as..." options.
Added support for disconnects.
