* Will reject attempts to LoadFrom(char *) with a null pointer.
* Now puts a null byte in the tail end of the buffer during a
SaveTo(char *) even if the editor buffers are empty. Will
refuse to save to a null pointer.
* No longer writes extraneous null byte when saving to file.
* Added GetTextBufferSize() call on editorengine and Fl_Editor that returns
the number of characters that should be allocated in order to save the
text to a buffer. The CharacterCount() method returns only characters
actually presently in the buffer, while this new method considers the line
ending characters that would be added when saving.
