=== UnwrapText

Remove (best effort to) the hardcoded wrapping from a message.

If the text is  "format=flowed" then deflows the text. Otherwise it forces a dewrap of the text.


Parameters:

* quotewidth - when we try to dewrap e quoted text it helps knowing the original
with, so we can reconstruct "wrapped wraps" created by multiple wrappings by clients with
different original width or simply to the add of the heading ">" that increase the line
length.

The value should be "WIDTH+X" if the original length is known, "-X" otherwise.

In the latter case the length of the longer line will be used.

X is the tollerance needed for the quoting chars: if the original width is known the suggested
value for X is 2 (because of "> " prefix), otherwise it is suggested to increase it to a value
like 10 (-10)

In summary, if the original wrap is known (for example 76, for flowed messages) *quotewidth = 78*

Otherwise *quotewidth = -10*