Added missing is_nullary specialization.
Added operators for non-const object output.
Added a changelog entry for ticket 9389.
Added a changelog entry for ticket 9389.
Removed register storage specifier as it causes warnings on newer clang
versions.
Added support for bare filename and function name extraction in the
named scope formatter. Function name does not work yet if function types
are present in the scope (function) signature.
Documented the new flags for format_named_scope.
Performance optimization.
Fixed compilation of get_attribute method of loggers.
Silenced GCC warnings about unused variables.
Silenced "missing return statement" warnings.

On compilers without support for unreachable code or noreturn hints
generate dummy return statements to silence warnings.
Added another (not yet working) test for named scope format parser.
Fixed parsing signatures of functions that return function pointers.

- Function name parsing is only done for scopes denoted with
BOOST_LOG_FUNCTION, scopes marked with BOOST_LOG_NAMED_SCOPE are output
as is.
- The parser has been rewritten to behave more correctly in case if
function name contains template parameters and/or returns a function
type.
- Operator functions are not supported by the parser.
- Docs corrections.
Added more operator testcases.
Added MSVC-specific testcases.
Removed register keyword.
Fixed incorrect test case.
New version of function signature parser.

The new version supports operators and is more resilient to the input
format variations. It should no longer get confused by the space
characters between the function name and the opening parenthesis.
Minor optimizations.
Updated MSVC-specific test case with array return type.