Merged Signals2 from sandbox to trunk.
Trying to fix compile error on mutex_test.cpp on msvc9
Quiet a compiler warning on msvc 7.1
Trying to fix compile error of some test programs on compilers that don't 
support void returns.
Added const qualification to no_slots_error::what().
Fixed "looser throw specifier for virtual" compile errors.
Deal with compile errors caused by enable_shared_from_this reversions.
Added check to make sure postconstructor_invoker doesn't call
adl_postconstruct multiple times.
Trying to work around msvc 9 apparently compiling unused member f
unctions in templates.
Removed obsolete Makefile.
Added copyright comments to boostbook xml files.
Replaced tab indentation with spaces, added a missing copyright/license.
some inspect cleanups (mostly getting rid of tabs).
Trying to work around msvc 7.1 bugs in some tests.
Finally fixed some odd test errors on msvc9.
Generate code snippets using bjam instead of checking them into
svn, to avoid bogus entries in inspect report.
quote destination dir to deal with spaces.
Tweaked generation of Signals2 code snippets a bit.
Fix a couple of minor signals2 documentation issues.
Fixed a few more copyright/license issues detected by
inspection report.
Fix for broken links from Danel James.