convert-ly rules: word boundaries

[Graham Percival]

(cleaning up old emails)

This looks sub-optimal:
------
def conv (str):
    str = re.sub (r"\\octave(?![a-zA-Z])", r"\\octaveCheck", str)
    str = re.sub (r"arpeggioUp", r"arpeggioArrowUp", str)
    str = re.sub (r"arpeggioDown", r"arpeggioArrowDown", str)
...
------

arpeggio* should have \\ as well.  Also, they should also be
matched with full words.  In fact, 99% of the convert-ly rules
need to match a complete word.  According to Daniel Hulme,
"\\octave\b" would work fine.

1)  Could somebody verify this (look in the python docs, run a few
tests, whatever... not that I doubt Daniel; just that we should
make sure).

2)  Could somebody consider writing a nicely-named-function such
that the convert-ly rules look like this?

def conv (str):
    str = f("\\oldCommand", "\\newCommand", str)
?

It's silly for people to manually add \b everywhere, and it's
equally silly for contributors to say "oh, I can't touch
convert-ly, since I don't know python".  Let's make it easy to
write/modify those rules.

Cheers,
- Graham