Sorry for the long delay between versions, but here is graphDS v0.8! I think that you'll find it worth the wait. I made some pretty substantial additions, so please download.
Additions/changes:
-Two new graph modes: slope field and Euler's method.
-Added a CAS to simplify algebraic expressions, including foiling
-Increased calculation and graphing speed by 2.5x
-Made function nIntegrate faster and more accurate
-Added new catalog functions for approximating definite integrals: euler, monteCarlo, simpson, trapezoid