More multichar goodness

The "active" character can now be any one of those in the text box, not always the first one shown.

Clicking a char makes it the active "editing" char. This might mean there are chars to the left and right of the active one.

Word list processing changes the current active char to the first one on the line, instead of locking in whatever the previous active char was.

Tab labels are now updated to reflect the multichar editing. Likewise the window title is updated to reflect the editing char when that changes.