Problems with Undo when removing all text of the editor

[raphaelcruzeiro]

Currently, the editor is unable to perform a Undo command when all text text of the editor is removed. This is probably because of the placeholder text logic.

[raphaelcruzeiro]

Perhaps the placeholder should be placed outside the editor (maybe a pseudo-class?)
@otaviosoares what do you think?

[otaviosoares]

I totally agree. Separate concerns of placeholder and content is the way to go.

[raphaelcruzeiro]

Unfortunately, the solution for this caused a more serious bug (#59).