update to rad_plot

[alexbaras]

synthetic data example to plot

last line shows how to call

`d = np.random.uniform(-1, 1, [10000, 2])
i = np.random.randint(0, 20, 10000)
s = np.arange(20)
s_d = np.random.uniform(0, 1, int(20 * (20 - 1) / 2))
l = np.concatenate([np.repeat('A', 10), np.repeat('B', 10)])
l_dict = {'A': 'blue', 'B': 'red'}

rad_plot(d, s_d, s, l, i, l_dict, self=None, plot_type='2dhist', vmax=0.001, dg_radius=0.2, axes_radius=0.3, gridsize=50, n_pad=2, gaussian_sigma=2)`

[alexbaras]

example plot for completely random data