v0.5.0

• Many many bug fixes
• Revise all examples in the documentation
• Revert to default float64 dtype instead of float32 to avoid precision errors
• Improve verbose training output
• Improve plots slightly
• Add mogptk.gpr.MultiOutputMean, support for different mean functions for each output dimension
• Make all randomness come from PyTorch and not also numpy
• Revert memory optimization for exact model to avoid Cholesky problems
• Add prediction confidence intervals and likelihood sampling