(tex-font-lock-keywords-1): Fix ARG regexp to skip quoted braces.

(tex-font-lock-keywords-1): Fix ARG regexp to skip quoted braces.
(tex-font-lock-keywords-2): Fix ARG regexp to skip quoted braces.
Remove `bf' and `it' from `bold' and `italic' (they were wrong and
are (correctly) handled separately).
Remove `caption' and `footnote' from `citations': they contain text.
Don't highlight `textmd', `texttt' and `textrm' with bold-italic.
(latex-skeleton-end-hook): New function.
(latex-mode): Use it.
(tex-start-tex-marker): Remove.
(tex-send-tex-command): Don't set tex-start-tex-marker.
(tex-error-parse-syntax-table): New var.
(tex-compilation-parse-errors): Use it.
Ignore tex-start-tex-marker.  Don't bother with marker-position.
(tex-validate-buffer): Don't bother with marker-position.