Options for initial line/column values

[thorn0]

Feature Use Case

When CSS values are parsed as part of CSS files, for AST consumers (e.g. code formatters), it is sometimes more convenient if the location data of all AST nodes is relative to the file, not to separate values.

Feature Proposal

Add parser options initialLine and initialColumn.

[shellscape]

I'd probably go with sourceLine and sourceColumn to give a better context. But nice idea that.