Remove obsolete MSVC check from pragma guard

 git grep -h -B1 "^#\s*pragma once" | grep -v pragma | sort | uniq

is now clean.

[SVN r85952]
cast: Remove obsolete MSVC version check.

[SVN r86026]
lexical_cast: Remove obsolete GCC version check.

[SVN r86113]
Simplify multi-component ifdefs containing BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

[SVN r86248]
Supressing MSVC2013 warnings and ensuring that lexical cast io classes are not copied (refs #9271)

[SVN r86374]