Provide line number and file name for debugging embedded c#

When using the function syntax for providing C# code, this uses the v8 callstack api to provide the line number of the c# and the name of the javascript file to the language compiler to aid debugging.

Caveats:
1. This only works if the function providing the C# code is included inline as a parameter to the func function.
2. This is relatively fragile to any refactoring of edge.js that changes the callstack between the user's script and the code using the callstack.

ref: #6