context: merge of 80553 (impl)

svn path=/branches/release/libs/context/; revision=80572
context: support for Mac OS X 32 bit

svn path=/branches/release/libs/context/; revision=81323
context: merge from trunk (replace align_stack() by assembler; remove stack-allocator)

svn path=/branches/release/boost/context/; revision=81611
context: bufix (Mac OS X)

svn path=/branches/release/libs/context/; revision=81630
context: bugfix for 64bit Mac OS X

svn path=/branches/release/libs/context/; revision=81686
context: merge from trunk

svn path=/branches/release/libs/context/; revision=81719
context: merge from trunk

svn path=/branches/release/libs/context/; revision=82142
context: merge from trunk

svn path=/branches/release/boost/context/; revision=82500
context: merge from trunk (SPARC support)

svn path=/branches/release/boost/context/; revision=82601
context: revert support for SPARC

svn path=/branches/release/boost/context/; revision=82626
context: merge documentation from trunk

svn path=/branches/release/libs/context/; revision=82666
context: merge from trunk (SPARC support)

svn path=/branches/release/boost/context/; revision=82829
context: merge from trunk

svn path=/branches/release/libs/context/; revision=84199