Dynamics do not unnecessarily horizontal shift for stems. (issue 6493073)

[dak]

http://codereview.appspot.com/6493073/diff/1/lily/self-alignment-interface.cc
File lily/self-alignment-interface.cc (right):

http://codereview.appspot.com/6493073/diff/1/lily/self-alignment-interface.cc#newcode213
lily/self-alignment-interface.cc:213: vector_sort (vais, less<int> ());
Seriously?  If dir is UP, you are interested in the minimum, and if it
is DOWN, you are interested in the maximum.  And you create a vector and
sort it for that?

Totally inefficient as well as incomprehensible.

http://codereview.appspot.com/6493073/diff/1/lily/self-alignment-interface.cc#newcode280
lily/self-alignment-interface.cc:280: "potential-X-colliding-grobs "
Does normal-stems need to be here?

http://codereview.appspot.com/6493073/