Improves TeX log parsing.

 * Log messages with only opening parenthesis would trigger a new file instead of contributing to the message. Hacked in other direction. Good?
 * File-line-error messages allowed to few file names; now, all whitespace-free file names are allowed.
 * Detects LaTeX Font Warning messages now.
 * Detects runaway text (and other runaway) messages now, not only runaway arguments.