VecEM

Added files:

#!c++
   TCashKarpRKF45.hh
   TMagFieldEquation.hh
   TCachedMagneticField.hh
   TQuadrupoleMagField.hh
   TMagErrorStepper.hh
   TClassicalRK4.hh
   TUniformMagField.hh

Test:

• /test directory is here
• read the functionality report

BenchMark:

• /benchmark directory
• read the benchmark report