fix #32391: center lyrics under whole notes
fix #17190: left align hyphenated melismas
add vtests
Enter Edit Mode on an element only if if it isEditable()

Currently, `Element::isEditable()` is not checked before entering edit mode. This PR adds the checks.

**Note**: Given the variety of conditions which may determine the editability of an element and the fact that so far the `isEditable()` method has been under-utilized, this may lead to making un-editable elements previously editable (possibly correctly or possibly not).
Merge pull request #1300 from mgavioli/Edit_element_only_if_isEditable

Enter Edit Mode on an element only if isEditable()
update Gonville

see http://musescore.org/en/node/24199#comment-137926
update vtests for Gonville
Merge pull request #1302 from Jojo-Schmitz/gonville

update Gonville
Merge pull request #1286 from MarcSabatella/32391-lyric-center

fix #32391: center lyrics under whole notes