update readme

README.md

@@ -15,6 +15,10 @@ Rust scientific computing for single and multi-variable calculus
 - Supports linear, polynomial, trigonometric, exponential, and any complex equation you can throw at it, of any number of variables!
  - Single, double and triple differentiation - total and partial
  - Single and double integration - total and partial
+ - Booles
+ - Gauss Legendre (upto order = 20)
+ - Simpsons
+ - Trapezoidal
  - Jacobians and Hessians
  - Vector Field Calculus: Line and flux integrals, curl and divergence
  - Approximation of any given equation to a linear or quadratic model