Make vector print function in examples be more correct.
Fixes #6677.
Improve error reporting.

The name of option is now shown in most cases when it's feasible, and
clarify of the error messages has been improved throughout.

Patch from Leo Goodstadt.
Allow to specify how option's value is named in help message.

Fixes #4781.
Summary: Moved libs/detail/utf8_codecvt_facet.cpp to boost/detail/utf8_codecvt_facet.ipp
Author: Dave Abrahams <dave@boostpro.com>
Include necessary header, don't rely on two-phase lookup not being there.

Fixes #6790.
Adjust spelling.
Fix compilation error.

Fixes #7049. Patch from Deniz Bahadir.
Qualify 'distance' with 'std'.

Fixes #7086.
Fix warnings on 64-bit systems.

Closes #7077.
Fix indent
Really fixes #7049.
Revive exception_txt_test. 

Found while working on #8009.
Fix report of error for options with dashes.

Fixes #8009.
Patch from Markus Roth.
Silence gcc warning. Thanks to Chris Stylianou.

Closes #8725.