Changes in Version 0.1-4

o now uses jython.jar and separate sympy tree

o upgraded to Jython 2.5.1 and sympy 0.6.5

o now depends on rJava 0.8-1

Changes in Version 0.1-3

o new "Sym" class with constructor Sym and methods as.character.Sym, 
  as.expression.Sym, derive.Sym, Math.Sym, Ops.Sym, print.Sym, solve.Sym,
  t.Sym

o new functions: Eye, Integrate, Limit, List, Matrix, Zero, Zeros

o new function: Var

o sympy has new retclass= argument

