3.0.0 release

Compatible with Nengo 3.1.0

Added

• The benchmarks in the examples folder now have nicer command-line interfaces. Use the --help flag with any benchmark to learn more about the options. (#187)
• The new examples/benchmark_backends.py script makes it easier to compare between different backends on any of the benchmarks. (#187)

Changed

• Sparse matrix multiplication is now faster in many cases by using the ELLPACK matrix format. It uses more memory for some sparse matrices, though; for matrices where it would result in a large increase in memory usage, we fall back on the old CSR format. To force a particular format, set the NENGO_OCL_SPMV_ALGORITHM environment variable to either "ELLPACK" or "CSR". (#188)
• Made NengoOCL available under the GPLv2 license. (#191)

Removed

• Dropped support for Python 3.5. (#187)