Remove FreeBSD checks when defining USE_WCHAR_T.

The problems the comments in the build systems refer to seem to have been
fixed for years. [1] says the checks in libstdc++ have been improved, and
all supported FreeBSD versions enable wchar_t support unconditionally in
libstdc++. Additionally, this needlessly impacts FreeBSD when libc++ is used
instead of libstdc++.

[1] http://gcc.gnu.org/onlinedocs/libstdc++/faq.html#faq.freebsd_wchar
Advanced F&R dialog does not need to be restored at start-up.
fix copy-paste error
Translation update for nb.po. More and better beamer translations,
as well as clearing up fuzzy items all over the file.
Fix crash when using context menu in empty outliner

Fixes: #8885
Update po/gmo files
Update it.po
This is lyx2.1.0beta2
Improve beamer frame conversion: consider explicit EndFrames between two identical frame types
de.po
powerdot: fix argument order with empty first argument
enumitem module: one forgotten adaptation to new argument possibilities
We only have the last LyX release in the export menu (the others are accessible via SendTo and SaveAs dialogs)

In general, the export menu looks much too crowded again. Should be audited if really all these items are needed on top level.
Fix encoding for copying LaTeX from clipboard

If we call tex2lyx on a temporary file created from the clipboard, the
file is always in utf8 encoding, without any temporary changes, even if it
contains encoding changing LaTeX commands. Therefore, we must tell tex2lyx
to use a fixed utf8 encoding for the whole file, and this is done using the
new latexclipboard format. Previously, tex2lyx thought the encoding was
latin1.
As a side effect, the -e option is now also documented in the man page.
Fix XeTeX export when using heb-article.layout

polyglossia is used by default and \make@lr is only defined
by babel. Modifying the preamble fixes XeTeX export and pdfTeX
continues to work.

See the following thread for more information:
  http://www.mail-archive.com/lyx-devel@lists.lyx.org/msg181220.html

Thanks to Enrico for the patch.
Fix export of Greek Intro manual with XeTeX

This is a workaround. Without this patch, export to .tex (XeTeX)
contains a sequence such as

  \begin{english}
  \begin{description}
  [omitted, but does not contain \end{description}]
  \end{english}

Thanks to Jürgen for the workaround.
Hebrew docs: move bookmarks inside of pdflatex if

This fixes XeTeX export of the Hebrew documents.
Fix bug 8880: do not try to validate custom value if it is disabled
Fix shortcut clash (bug #8878)

Patch by charley
Silence unwanted error popup on copying

The new HTML clipboard export could cause error message boxes on copying
data to the clipboard (bug #8866). These are now suppressed, like all other
errors which might occur for preparing the clipboard data.