Rebase changes for tests, decoupling and new features

Decoupling of metamodel from expdesign and model, expdesign is now child-class of inputspace, metamodelengine renamed to engine and responsible for all of the training. New features: UMBridge models and OLS with constraints in metamodel regression Tests: unit tests for inputspace, expdesign, metamodel almost complete, started on those for engine, model, and more Examples: run through on the new setup, two added examples for the new features