Don't assume SO_UPDATE_CONNECT_CONTEXT is defined.

Fixes boost trac ticket #10016.
Use VerifyVersionInfo rather than GetVersionEx.

GetVersionEx has been deprecated.
Fix off-by-one error in signal number check.

Fixes boost trac ticket #9324.
Return bytes transferred when ReadFile fails with ERROR_MORE_DATA.

Reverted the previous change to ignore ERROR_MORE_DATA. Instead,
the error will propagated as with any other (i.e. in an error_code
or thrown as a system_error). For code that needs to handle partial
messages, the error_code overload should be used.

Fixes boost trac ticket #10034.
Work around gcc problem to do with anonymous enums.

Fixes boost trac ticket #10042.
Use SSE2 intrinsics to allow the Cray compiler to work.
The intel compiler doesn't provide the SSE2 intrinsics.
Revision history.
Version bump.
Fix wording in revision history.
Merge asio 1.10.3 from 'develop'