Account for latex snippet width in fill paragraph

[Matt Huszagh]

Hello,

I make extensive use of inline latex image snippets in my Org
buffers. One thing that has annoyed me for a while is that
`org-fill-paragraph' (unsurprisingly) uses the width of the underlying
text when determining the characters which make up each line. Because
the characters which make up the source of an image are typically wider
than the image itself, this creates short lines when many snippets are
used. For example, the following text

```
This gives some degree of temperature-stability because although
\(V_{\mathrm{BE}}\) changes somewhat with temperature, the change is
small. If the quiescent output voltage is designed for say
\(10V_{\mathrm{BE}}\), and \(V_{\mathrm{BE}}\) varies \(\SI{0.1}{V}\)
over temperature changes, then the quiescent point will vary
\(\SI{1}{V}\) over temperature changes. This isn't great, but may
sometimes be good enough.
```

appears something like

```
This gives some degree of temperature-stability because although
VBE changes somewhat with temperature, the change is
small. If the quiescent output voltage is designed for say
10VBE, and VBE varies 0.1V
over temperature changes, then the quiescent point will vary
1V over temperature changes. This isn't great, but may
sometimes be good enough.
```

Before I take a crack at this, has anyone else attempted to remedy this?
I wasn't able to find anything on the mailing list. Would anyone else be
interested in this functionality? I figure a proper solution would
appear to the user as a configurable variable that could enable filling
based on image width (this behavior might be undesirable in some
cases). My currently uninformed view is that it should be possible to
query the overlay image width and perform a fill based on that. Any
thoughts, concerns, etc. are appreciated.

Matt