allow long error messages to wrap

@PjpG introduced a few styles to prevent long messages from stretching their table cells. `word-wrap: break-word;` + `width: 300px;` accomplish this. `white-space: nowrap;` was additionally causing exception messages to be truncated at 1 line; but this can make some errors difficult to read. Removing that style preserves the original intent but allows errors messages to wrap if they need to.
Merge pull request #403 from boblail/allow-word-wrapping

allow long error messages to wrap