Y and X labels in plotter function #5
Description
The code to plot mean, worst and 95th percentile emulations of the testing data currently only allows for the xlabel to be z and the ylabel to be $T_{21}$ [mk] and $x_{HI}$. This is generally okay as the code is primarily intended for emulation of the global 21-cm signal and neutral fraction however it would be useful to allow the user to specify the x and y labels. For example if the user requires a production copy of graph they may need to change the label $T_{21}$ [mk] to $\delta T_b$ [mK].
This should be easily implemented using some additional keywords.
Alternatively, it might be useful for the function to plot the results and then return the figure and axes to the user so that they can modify the details in their own code.