Support the "--nowrap" option

Currently this is only supported my mhng-show, which when passed
"--nowrap" will not wrap the output at all.
Have mhng-urls use $BROWSER, not firefox

This way users can configure their own browser if they want.
Use a better text-wrapping algorithm

This has two changes
* Wrapping is considered on a per-paragraph basis
* Common-prefix paragraphs aren't wrapped

This should greatly help with things like inline code and replies.
Add "mhng-bud", a Bash hUD

This shows a very small indicator of the current messages that exist,
which is useful for including inside a PS1 prompt.