Mopidy.js 0.4.0 released 2014-06-24 added support for the by-position-or-by-name calling convention, but the by-position-only calling convention is still the default.

Short term we should change the default. Long term we should remove the by-position-only calling convention.

We can change this now, but then we should not bundle the new release of Mopidy.js with Mopidy, so we don't break old clients, ref. mopidy/mopidy#1460.