CFL + Code improvements

Removed the requirement for a `parser-path` option.  Reason for doing this is primarily for testing purposes.  Now it won't run the exec command if this option doesn't exist.  Instead you can just pipe the output from the header parser and test the output simply by ignoring `parser-path`.  This is something that should be always be environment specific, so it shouldn't have a default.

Next, I pulled out 2 blocks of code and made an `_exec` function that takes the command and the `done` callback.  This function checks for the existence of the `parser-path` option and either executes the command, or just calls `done`.

Also added CFL mapping to hash.