New colour code for Not-for-profit organisations.

We have decided to slightly change the colour codes for the network graphs. This will make it easier to distinguish between the different types of organisations. From now on, Not-for-profit organisations will be coloured yellow! Institutions and companies will keep their previous colour codes, red and blue respectably.
Some of the graphs are still using the old colour codes, but they will soon be re-made to satisfy the new standard.