Added support for linebreaking of mmultiscripts.  Resolves issue #617.
Remove initial space after a linebreak properly.  Resolves #687.
If a break occurs at a space or operator that has non-zero width, don't remove next element's initial spacing.
Merge remote-tracking branch 'dpvc/issue617' into develop.  Issue #617.
Merge remote-tracking branch 'dpvc/issue687' into develop.  Issue #687.