Updating version to 1.55
Merge fix for C++11 compilation error
Spirit: Merging from trunk
Fully merge boostbook from trunk.

- Optionally use section ids as a class name for CSS styling, by using the
  `boost.section.class.add.id` parameter.
- Add the `role` attribute to the class for `section` and `simplesect`.
- Update the single html template to be closer to the chunked html.
- Fix the encoding for single page html.
- Add option to permit single depth TOC at chapter level, while maintaining
  multi-depth TOC at subsequent levels. Use the `boost.noexpand.chapter.toc`
  parameter.
- Add some C++11 keywords to the syntax highlighter.
- Support the fixed-length `$Date:: $` subversion keyword in last-revision
  library attributes.
Merge unordered from trunk.

Add `BOOST_NOEXPECT` to:

- Move constructors (when appropriate)
- Destructors
- Iterators

Also, fix some misleading documentation about the containers' move support.
Merge iostreams - fix rethrowing an exception.
Merge quickbook. Starting 1.6 alpha, plus some 1.7 development.
Merge changes from trunk
Merge from Trunk
Polygon: merging fix of bug #8197 with release branch.
Merged recent changes from trunk.
Merged recent changes from trunk.
Merged recent changes from trunk. Fixes #8730.
[regression] Merged out-of-sync files from trunk to release. Make bin dir ignored.
Merge from trunk.
Merge bug fix to Release; Fixes #8546
Merged maintainers.txt from trunk to fix some issues mentioned in '[boost] Announcing boost dependency analyzer' mails (http://boost.2283326.n4.nabble.com/Announcing-boost-dependency-analyzer-td4649904.html)
merged [85001], [85004], [85005], [85016], [85017], [85018], [85022], [85028], [85099] and [85100] from trunk
Merge maintainers.txt fixes from trunk.
Merge from trunk:
* bad_any_cast exception is now visible across modules (fixes #8751)
* portion of optimizations and tests for rvalues
* added ability to call any_cast<T&&> (which is equivalent to std::move(any_cast<T&>))
* added clear() member function
* added missing BOOST_NOEXCEPT