Create copy constructor for Python

[larsgeb]

In Python, a lot of objects are mvoed around. When someone now creates and fdModel class and copies it, they actually reference the same object:

import psvWave

a = psvWave.fdModel("conf.ini")
b = a
a.set_model(...)

m = b.get_model() # same as the model just set.

I think this classifies as unexpected behaviour. There is no available copy constructor, and therefore to duplicate an fdModel object with its current state one has to go through the exercise of running all statements up to the duplication point multiple times.

To hide some of this complexity, a copy constructor should be created in C++ and interfaced to Python.

[larsgeb]

Added in 376eaa2.

Method that calls the C++ copy constructor:

psvWave/src/psvWave.cpp

Lines 324 to 327 in 376eaa2

	fdModelExtended *copy() {
	// std::cout << "Returning" << std::endl;
	return std::move(new fdModelExtended(*this));
	}

Python binding for the copy method:

psvWave/src/psvWave.cpp

Lines 370 to 373 in 376eaa2

	.def("copy", &fdModelExtended::copy,
	"copy() -> psvWave.fdModel\n"
	"\n"
	"Returns a copy of the object, duplicating all members.")