Spec fails to say how line numbers are computed.

The spec description of [`CallerLineNumber`](https://github.com/ljw1004/csharpspec/blob/gh-pages/attributes.md#the-callerlinenumber-attribute) says that it gives the line number of the caller, but nothing in the spec hints as to how that line number is to be calculated. For example, how are line numbers affected by a form-feed or vertical-tab appearing inside a single-line-comment or string literal? Is the first character in a source file on line zero or line one? Does a CR-LF combination add two or add one to the line count?