add function get_wave() to RawRead class

[mvanriet]

Now you have to do :

vin = raw.get_trace('V(in)')  
xdata = raw.get_axis()  
ydata = vin.get_wave()  
plt.plot(xdata, ydata)

For simulations without steps, it would be more convenient to be able to do this :

xdata = raw.get_axis()  
ydata = raw.get_wave('V(in)')  
plt.plot(xdata, ydata)

Even for simulations with steps, it would be more convenient :

for step in raw.get_steps():  
    xdata = raw.get_axis(step)  
    ydata = raw.get_wave('V(in)', step)  
    plt.plot(xdata, ydata)

[nunobrum]

This was included in the 3.1 version

[nunobrum]

@mvanriet it will also be included in the dev_space next commit