Avoid 'unused variable v' warning on msvc-10.0, msvc-11.0

Upgrade libstdc++ to 4.9 for clang-3.9 14/1z

Upgrade libstdc++ to 4.9 for clang-3.9 14/1z

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'

Silenced warnings about unused variables.

Restored dependency on tools/inspect in master.

Added a boostdoc target to unify Boost release docs building.

Added support for gabi++ ABI implementation used in Android NDK.