Add support for the concept of `fuel`. Limit execution of expressions to be constrained by this `fuel`.

[isubasinghe]

This would require some static analysis and dynamic analysis to build.
I can tackle this.

This issue is to add support for a fuel parameter when evaluating or compiling expressions. This fuel parameter can then be used to limit the execution window of an expression.

Currently expr cannot be used in outward facing code since we can't really "sanitize" expressions. So in order to prevent DOS attacks via malicious expressions, we should be able to limit the amount of cycles afforded to evaluating an expression.

Happy to tackle this if I get the go ahead that this will be accepted after it's implementation.