Added Comparison tables to the closure execution engine docs
Fixed table for N3558 comparison on closure_execution.qbk
Edits to the text in cosure_execution.qbk
Updated documentation for closure execution engines

Moved code to test/examples
Added appropriate lines to afio.qbk
Added closure_execution.qbk to quickstart.qbk and changed headings to be appropriate
Fixed extra [endsect] in afio.qbk
Missed commiting some changes to the example programs to make them work with quickbooks
Merge branch 'master' into closure_engine_docs
Changed headings to sections in the quickstart. Not sure we'll keep it.
Fixed an include so that preprocessor logic will work.

There is a redundant #include, but it should work now.
Fixed missing install instructions, and hopefully fixed an issue with vs2010 building an example
Missed commiting a #endif in an example.cpp
Merge pull request #39 from BoostGSoC/closure_engine_docs

Closure engine docs
Merge branch 'master' into async_dir_enumerate

Conflicts:
	libs/afio/doc/afio.qbk
Fixed typo