tm_rnet() titles and all

[temospena]

Add title option in tm_rnet, such as:

tm_layout(title = title, panel.show = T) + ...

Create a function (tm_rnet_multiple()?) to be able to show and hide more than one layer: different visualization for the same data

[Robinlovelace]

Yes this would be good...

[Robinlovelace]

Simple approach would be:

m = tm_rnet(...)
m + tm_layout(...)
``

No?

[temospena]

add an alpha option to tm_rnet, usefull when showing 2 layers at same time.