Added NetLogo language

Added the NetLogo programming language, a dialect of Logo—an adaptation of LISP.
From [Wikipedia:](http://en.wikipedia.org/wiki/Logo_(programming_language))
> Logo is a graphic oriented educational programming language, designed in 1967 by Daniel G. Bobrow, Wally Feurzeig, Seymour Papert and Cynthia Solomon. Today the language is remembered mainly for its use of "turtle graphics", in which commands for movement and drawing produced line graphics either on screen or with a small robot called a "turtle". The language was originally conceived to enable what Papert called "body-syntonic reasoning" where students could understand (and predict and reason about) the turtle's motion by imagining what they would do if they were the turtle. There are substantial differences between the many dialects of Logo, and the situation is confused by the regular appearance of turtle graphics programs that mistakenly call themselves Logo.

Source code for the language can be found @NetLogo .

Also added were 3 sample files:
- Ants.nlogo - An simple simulation of ants looking for food
- Life.nlogo - An implementation of Conway's game of life using patches
- Star Fractal.nlogo - A fractal design programmed in NetLogo

More models are available @NetLogo/models