[trunk] Dot of dotted note cannot be made invisible

Setup: trunk rev. 4208, Ubuntu 9.10, Qt lib 4.6.2

Steps:

1) Open or create any score containing a dotted note
2) Right-click the dotted note (head) and select "Set invisible"

Result: the note head become invisible, but the dot remains visible and there is no "Set invisible" command for it.

Expected result: right-click menu for the note dot lists a "Set invisible" command to make the dot invisible too, as it happens for instance for the stem.

Note: As an additional improvement: usually when one makes a 'note' (generically intended) invisible he also want the stem, the dot and the flag (if existing) to become invisible; so making the head invisible should make invisible all the note elements; on the minority of cases when only the head is needed invisible, the user may turn the other element(s) back on individually.