Changes on the RNG and new random nodes

[HungryProton]

Create a RNG (random number generator) custom object that can be passed around like any other data type.

Nodes using a "Seed" input would have an RNG input instead, the seed value would be moved to the "Create RNG" nodes.
This would allow having multiple type of RNG distributions (uniform, normal and so on).

We also need nodes to create random numbers and random vectors.