Note input cursor glitches for voice >1 when advancing into gaps

Ubuntu 14.04, GIT commit: 66cbc77

Two semi-related bugs.

Bug A:

1) new score, 4/4
2) measure 1, note input
3) switch to voice 2
4) enter 4 quarter notes
5) press left arrow

Result: cursor - which had correctly moved into measure 2 after entry of the fourth note - moves backwards two spaces, to the note on beat 3. Voice 1 works as expected. It's the fact that there is no chordrest at the input position that triggers this behavior.

Bug B:

1) use score created above, including the four quarter notes
2) exit note input mode
3) click first quarter note, re-enter note input mode
4) press right arrow three times to advance to last quarter note
5) press Delete
6) press right arrow
7) press left arrow

Result: cursor will not move. Even though there *is* a rest at the input position, we aren't using it correctly.

I have fixes for both of these I will submit shortly.