libgfx: Vector Math
Author: Michael Garland

## Vector Math

### class Vec2

This class implements a 2-dimensional real-valued vector. Individual elements are represent with `double` precision floating point numbers. To use the `Vec2` class you must include the header

        #include <gfx/vec2.h>

#### Constructor Methods

The `Vec2` class defines the following set of constructors:

        Vec2();                    // Initializes vector to (0 0).
        Vec2(double x, double y);  // Initializes vector to (x y).
        Vec2(double s);            // Initializes vector to (s s)

        Vec2(const Vec2& v);       //
        Vec2(const float  v[2]);   // These copy values from v
        Vec2(const double v[2]);   //

#### Specialized Functions

Beyond the standard functions supported by all vector classes, the `Vec2` class provides the following additional function:

        Vec2 perp(const Vec2 &v);

that returns a new vector which is perpendicular to the given vector.