Disable electric-pair-mode conditionally.

* latex.el (LaTeX-common-initialization): Move disabling of
`electric-pair-mode' from `VirTeX-common-initialization'.  Disable
it only if `LaTeX-electric-left-right-brace' is non-nil.

* tex.el (VirTeX-common-initialization): See above.
Skip comment or file in parens in output.

* tex-buf.el (TeX-parse-error): Skip comment (or file) between
parentheses.

Signed-off-by: Tassilo Horn <tsdh@gnu.org>
Revert "Skip comment or file in parens in output."

This reverts commit 363b751003c4b425b4b6c511740c95366481207c.
Handle package messages with parenthesized text.

* tex-buf.el (TeX-parse-error): Don't confuse ) in package
messages with EOF.
New style files and a fix to imakeidx.el.

* style/imakeidx.el ("imakeidx"): Move addition of options to
`LaTeX-imakeidx-indexsetup-options' inside the hook.

* Makefile.in (STYLESRC): Activate new styles.

* style/fontspec.el: New style.

* style/luacode.el: Ditto.

* style/metalogo.el: Ditto.

* style/unicode-math.el: Ditto.