Macro parameter escaping

Macro parameters currently need escaping when containing curly braces. For example, the following fails to render properly:

{{box title="{{info}}test{{/info}}"}}this is a test{{/box}}

Parts of the info tag gets added to the content of the box instead of into the title.  It does work when the info is escaped properly:

{{box title="~{~{info~}~}test~{~{/info~}~}"}}this is a test{{/box}}

This is inconsistent with the way that the WYSIWYG editor sets parameters.