add a performance page to the wiki

[laurentopia]

the question i have is “how much do i pay for the convenience of using this graph vs pure c#?” a page showing bluegraph vs c# benchmarks would help answer.

considerations: allocation pressure, speed loss, cost of graph traversal, cost of graph instantiation.

tests types:

1. data crunch graph like the texture example vs c# equivalent
2. fsm graph vs c# switch case
3. simple branching in bluegrap vs nested ifthenelse in c#
4. instantiating N gameobjects with BG vs with c#

N=10k which helps evaluate BG impact on CPU starved devices