remove nb-configuration.xml
add nb-configuration.xml into .gitignore
put away the layouts of TriangleContourBuilderDemo
uncomment test2DQuadric() in SimpleGradientSolverTest
fix a bug that missing getSolution feature in NloptAdapter
Simplify ImplicitFunctionSolver

  + in itself
    + remove getEvalTimes()
    + remove getFunction()
    + remove getSolutionError()
  + accordingly remove relative @Overrides of SimpleGradientSolver
add MMAFunctionSolver and its tests