Text attachments & too-large images are problematic

[Deadpikle]

An issue was reported where images that were too large for the current display didn't look right in the text editor. A fix was applied (#10), but it seems as though saving to/from RTF with text attachments loses pertinent data.

One potential option that still needs research would be to use DTCoreText as a submodule and save/load to HTML that way, perhaps saving whatever custom HTML attributes are needed along the way.