Boost.Atomic and Boost.Lockfree merged from trunk.

[SVN r81976]
atomic: merge fixes from trunk



[SVN r82074]
Removed unnecessary fences, added pause operations to tight spin loops to optimize power consumption and performance on HT-enabled systems.

[SVN r82154]
Attempt to fix compilation on Windows CE. Restored full fence in the platform_fence_after_load function on architectures other than x86 and x86_64. The fence is not required only on those architectures.

[SVN r82157]
Added missing atomic typedefs.

[SVN r82168]
Fixed compilation on PGI.

[SVN r82184]
Attempt to fix compilation in Windows CE.

[SVN r82204]
atomic: merge documentation fix from trunk



[SVN r82570]
Atomic: merge from trunk.

[SVN r83533]
atomic: merge fixes from trunk



[SVN r84400]
Merged recent changes from trunk.

[SVN r85092]
Merged recent changes from trunk.

[SVN r85604]
Merged changeset 85793 from trunk.

[SVN r85969]
Merged changes from develop.
Merge branch 'develop'
Extracted all capability macros to separate headers.
Merge branch 'develop' into decouple_interface_impl_rewrite
Merge branch 'develop' into decouple_interface_impl_rewrite
Ranamed header.
Reworked capabilities definition. For all platforms, added BOOST_ATOMIC_INTn_LOCK_FREE macros that define the support for fixed sized integers. Other macros are deduced from the new ones, according to the native type sizes.