beast improvements and fixes:
* New maybe_const_t alias for maybe_const
* New safe_bool using C++11 features
* Fix is_call_possible metafunction:
   - Works on empty argument lists
   - Works with reference types
* Move IPAddress function definitions to the header
* Move cyclic_iterator to container/
* Remove unused BufferType
* Remove obsolete classes:
   - NamedPipe
   - ReadWriteLock
   - ScopedReadLock
   - ScopedWriteLock
   - LockGuard
beast::asio improvements
* New enable_wait_for_async for safe cleanup
* New memory_buffer, a managed asio compatible buffer
* shared_handler improvements:
  - Can be 'empty' (no stored handler).
  - Default constructible as 'empty'.
  - Safe evaluation in bool contexts, false==empty
Add streams module

Conflicts:
	src/beast/Builds/VisualStudio2013/beast.vcxproj.filters