1. Make inclusion of boost/bind/bind.hpp conditional in some cases, when the
   code actually conditionally uses boost::bind. Reduces compile-time overhead
   and fixes boostorg#307.

2. Remove some unnecessary uses of boost::ref. This allows to avoid including
   boost/core/ref.hpp in a few places, and avoids the associated template
   instantiation overhead in others.

3. Replace deprecated header includes with the more recent alternatives. For
   example: boost/detail/lightweight_test.hpp -> boost/core/lightweight_test.hpp,
   boost/ref.hpp -> boost/core/ref.hpp.

4. Replace some blanket includes with the more fine-grained ones. For example,
   boost/utility.hpp, boost/atomic.hpp. This reduces compile time overhead.

5. Add some missing includes, for example, boost/core/ref.hpp and
   boost/type_traits/is_same.hpp.

6. Replace uses of std::is_same with boost::is_same (with the corresponding
   included header) since the standard type_traits header presence and validity
   is not tested by the code. Using boost::is_same makes the code more portable.

This is to prevent multiple definition of the symbol when the file is included from multiple modules.

We use automatic dependency tracking for #includes, and wrl includes have to be tracked differently whenever we are cross-compiling the code.

This PR unifies such tracking. Forward slashes work just fine on Windows.

Boost.StaticAssert has been merged into Boost.Config, so remove
the dependency.

…ssert

Remove dependencies on Boost.StaticAssert

…ader

add missing assert header in pthreads_helpers.hpp

Use forward slashes to separate include files

Fix typos in copyright headers.

Cleanup header includes

Non-template function needs inline

Closes boostorg#382.

Also fix code indentation.