Update examples with CES.jl loss functions and other cleanup

[odunbar]

Content

Closes #52

• fix rng_seed bug and remove print statements in nd->md example
• add complexity term to nd->1d example
• remove the matching-cov, and loss function examples to make it clearer about our advocated approach in the with-cov examples
• updates Methods/runtests example based on nd->1d matching-cov, to now use results from with-cov

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