New FOS license for the YafaRay project

At the beginning of this project in 2001, the Lesser GPL 2.1 license was chosen because it allowed for integration of our rendering libraries in both FOS and propietary software with few limitations.

However, we are at a point where we need a license upgrade to stay compatible with the latest open source releases made by big studios and chip makers, particularly open source libraries released by Pixar and Disney and optimisation kernels released by Intel and AMD. These releases are usually made under the liberal Apache 2.0 license, which is not compatible with our LGPL 2.1 license because of patent litigation issues.

However, there is not a clear path for the license upgrade and anyway we would like to have input from as many people as possible to make the jump, paticularly from YafaRay users, developers of host applications and maintainers of exporters. You can find the discussion thread here. Thanks in advance.