make-connected-path-stencil should not hard-code the path origin at (0 0)

[Paul Morris]

Greetings Bug Squad,

Currently the function "make-connected-path-stencil"[1] does not allow you to 
specify the starting point (origin) of the path, but arbitrarily hard-codes it 
as (0 0).  This makes the function less flexible for no good reason. 

(Well, at least none that I can see, unless for some reason the code that 
calculates the size of the stencil depends on it, but that seems unlikely.)

I think it would make more sense for the origin to be defined by the first 
point in the "pointlist" argument.  A proposed revision making this change is 
in the attached file.  It contains a revision of this function, as found in 
stencil.scm in the LilyPond source code (including David Kastrup's recent 
improvements[2]).  The changes start at line 77.

(I suppose that if this change went forward then convert-ly would need to add a 
"(0 0)" in the appropriate place to explicitly set the path origin wherever 
this function has been used, to keep from mangling existing stencils...)

Thanks for considering,
-Paul

[1] http://lsr.dsi.unimi.it/LSR/Item?u=1&id=891
[2] http://code.google.com/p/lilypond/issues/detail?id=3624