evaluate perl code in context wrapper

 Eval::Context defines a subroutine that lets you evaluate Perl code in a
 specific context. The code can be passed directly as a string or as a file
 name to read from. It also provides some subroutines to let you define and
 optionally share variables and subroutines between your code and the code you
 wish to evaluate. Finally there is some support for running your code in a
 safe compartment.