EHTMLEditorSelection - Avoid runtime warning when trying to cast DOMText to DOMElement
EHTMLEditorView - Wrap and quote just the first block after newly inserted line into the citation

Previously, the whole blockquote that was created after the newly
inserted line was wrapped and quoted. Now just the first block is
processed. Also rewrap the content as when enter was pressed in the
middle of the paragraph the line ends wouldn't match the character
count for word wrap.
EHTMLEditorView - Don't put quote characters after the anchor when it is in the middle of the quoted text
EHTMLEditorView - When the link has non-breaking space in the prefix skip it
EHTMLEditorView - Don't put unnecessary new lines in the quoted content when generating the plain text version of the message