EasyFeynDiag

An extended version of the simple and fast Feynman diagram generator easyfeyndiag. The main improvement in this version of EasyFeynDiag is to prohibit equivalent Feynman diagrams to two-loop order (while the previous version is to one-loop). The symmetry factor calculation with equivalent diagrams prohibition to two-loop is a nontrivial problem, which is well solved in the new program. The code of the program is also reorganized, hopefully in a way more convenient for people to read.