Indeed, if the user is passing the switch `-Ymacro-expand:somethingelsethannone`, which is the only thing that makes sense for a < 2.11 compiler, we should not remove it. That being said, whether or not `project.isUsingCompatibilityMode()`, the filter `!arg.startsWith("-Xsource") && !arg.startsWith("-Ymacro-expand:none")` _isn't_ going to remove it _anyway_.

If the user is passing `-Ymacro-expand:none`, we should filter it :
- if the compiler is a 2.10 flavor, *it will break*
- if the compiler is a 2.11, the option is useless in a build context.

Excerpt from the doc:
> Don't expand macros. Might be useful for scaladoc and presentation compiler, but will crash anything which uses macros and gets past typer.