Issue 4541 (2/2) Clean up...

Issue 4541 (2/2) Clean up...

* Use has_interface<Interface> (grob)
* Remove DECLARE_GROB_INTERFACE()

Edits to grob-interface.hh are manual and the rest is the result of
the following script.

for FILE in $(git grep -lw DECLARE_GROB_INTERFACE lily)
do
    sed -i "/^ *DECLARE_GROB_INTERFACE ();.*$/d" $FILE
done

for FILE in $(git grep -lw "has_interface" lily)
do
    if [ $FILE == lily/include/grob-interface.hh ] ; then continue ; fi

    sed -i "s/\\([_a-zA-Z]\\+\\)::has_interface\\>/has_interface<\\1>/g
s/\\([_a-zA-Z]\\+\\) && has_interface<\\([_a-zA-Z]\\+\\)> (\\1)/has_interface<\\2> (\\1)/g" $FILE
done