outside-staff-placement-directive.ly

[mike]

Hey all,

The regtest outside-staff-placement-directive.ly is currently not doing what 
it's supposed to because of \textLengthOn, which masks the effects of the 
placement algorithm.  I must have inadvertently added that during a moment of 
sleeplessness...

I'll propose a patch fixing this unless someone sees a good reason to keep it 
this way.

Cheers,
MS