Feature/19 initialize with grid

[artem-ogre]

Implement functionality to use any custom geometry as a target instead of a super-triangle. InitializeWithGrid.h contains functions to initialize triangulation with regular or irregular grids:

/**
 * Make a triangulation that uses regular grid triangles instead of
 * super-triangle
 *
 * @tparam T type of vertex coordinates (e.g., float, double)
 * @param xmin minimum X-coordinate of grid
 * @param xmax maximum X-coordinate of grid
 * @param ymin minimum Y-coordinate of grid
 * @param ymax maximum Y-coordinate of grid
 * @param xres grid X-resolution
 * @param yres grid Y-resolution
 * @param out triangulation to initialize with grid super-geometry
 */
template <typename T>
void initializeWithRegularGrid(
    const T xmin,
    const T xmax,
    const T ymin,
    const T ymax,
    const std::size_t xres,
    const std::size_t yres,
    Triangulation<T>& out)

/**
 * Make a triangulation that uses irregular grid triangles instead of
 * super-triangle. Irregular grid is given by collections of X- and Y-ticks
 *
 * @tparam T type of vertex coordinates (e.g., float, double)
 * @tparam TXCoordIter iterator dereferencing to X coordinate
 * @tparam TYCoordIter iterator dereferencing to Y coordinate
 * @param xfirst beginning of X-ticks range
 * @param xlast end of X-ticks range
 * @param yfirst beginning of Y-ticks range
 * @param ylast end of Y-ticks range
 * @param out triangulation to initialize with grid super-geometry
 */
template <typename T, typename TXCoordIter, typename TYCoordIter>
void initializeWithIrregularGrid(
    const TXCoordIter xfirst,
    const TXCoordIter xlast,
    const TYCoordIter yfirst,
    const TYCoordIter ylast,
    Triangulation<T>& out)