* Unfortunately, due to the SWIG dependency, we need sudo to install on
Travis (conflicts when adding with debian-sid source prevent using addons)
which means we cannot use the container-based infrastructure anymore.
* Building the Python bindings requires g++5 (at least with -Werr set).
* When building the Python bindings on Travis, the numpy includes are not found
by cmake, so they have to be added separately by running a Python process with
`numpy.get_include()`
* The build script now (somewhat clumsily) depends on the RUN_PYTEST environment
variable. If it is set to anything other than "", it will make the tests and
run tests and benchmarks
* Add requirements.txt file with required Python packages
* Read requirements.txt from CMakeLists.txt to check dependencies and alert the
user if necessary.
* Add SWIG interface definition (and external numpy interface) to ecl classes
* Add section in CMakeLists.txt to build Python bindings and execute
Python-based tests
* Write (property-based) tests that show the basic functionality of the Python
bindings and the EKF (using pytest and hypothesis libraries)
* Write minimal benchmark for the EKF update (using benchmark plugin for pytest)
* Add plotting utilities to analyze tests
* Add lint script to keep the Python scripts clean
* This is a sane choice (and should arguably always be done for classes with
virtual methods to avoid undefined behavior)
* It is required for wrapping the EstimatorInterface with SWIG (without virtual
destructor, deriving from the EstimatorInterface leads to
-Werror=delete-non-virtual-dtor).
* For some reason cppcheck complains with `fp != nullptr` but accepts truthiness
of handle by itself.
* Note that the expressions are equivalent according to the C++ standard ("A
prvalue of arithmetic, unscoped enumeration, pointer, or pointer to member
type can be converted to a prvalue of type bool. A zero value, null pointer
value, or null member pointer value is converted to false; any other value is
converted to true. A prvalue of type std::nullptr_t can be converted to a
prvalue of type bool; the resulting value is false.")
Peter Dürr