Update release notes to mention .Net 3.5 support
Random: MersenneTwister.Default (thread-safe)
Random: use thread-safe mersenne twister instead of System.Random as default fallback
Tests: always seed RNGs
LA: Build.RandomPositiveDefinite; Build.Random with standard dist+rng
LA: build random with standard distribution, seed
Tests: simplify matrix structure theory tests by using matrix builders
Tests: refactoring towards generic builder 1
Tests: refactoring towards generic builder 2
LA: Matrix ConjugateTransposeAndMultiply and variants
LA: concrete conjugate and negate