EHTMLEditorSelection - Avoid the runtime warning when the caret was saved outside of the body

This could happen during the HTML -> plain text conversion.
EHTMLEditorSelection - Disable the selection-changed callback when restoring the caret position
EHTMLEditorView - Avoid extra new line when quoting the text

Don't insert the unnecessary BR element before the BR element that is
used for wrapping as it will end in unnecessary new line.
EHTMLEditor - Use get_parent_block_node_from_child where possible

This will ensure that the right node (the block node) will be returned
when the selection is saved inside the bold/italic/underlined text or
inside the anchor.
EHTMLEditorView - Fix the HTML structure after the selected text inside the quoted content is deleted