Import those parts of BOOST 1.56.0 that we need for deal.II.

This includes renaming the existing directory and overwriting every
file with the corresponding one from BOOST 1.56.0. Then removing thos
parts of the boost sublibraries that we don't need but that for
some reasons were included previously. Specifically, this applies to
documentation and build directories in libs/ and to the fusion and
spirit libraries that consist exclusively of header files.
Update test output.
Adapt a patch from around the internet to fix an issue with gcc 4.6.
Remove an obscure comment that does not enlighten anything at all.
Merge pull request #112 from bangerth/doc-fixes-7

Remove an obscure comment that does not enlighten anything at all.
Fix test output.

The recent changes to what get_name() returns for finite element objects did not update this output file.
Fix this.
Merge pull request #113 from bangerth/fix-test-output

Fix test output.
Add a default value for spacedim.

This matches all other existing places where we have both
'dim' and 'spacedim' as template arguments.
Merge pull request #114 from bangerth/fix-default-template-argument

Add a default value for spacedim.

This matches all other existing places where we have both
'dim' and 'spacedim' as template arguments.
Merge pull request #107 from bangerth/update-boost

This is a patch to update boost to the latest version, 1.56.0.
Add documentation to the manifold module.

In particular, give an example of why it matters and a few code snippets and pictures
that show how it works.
Provide a link to the manifold documentation module.

Also provide more discussion and fix a number of oversights in the
current version of the documentation.
Add another cross reference.
Merge pull request #115 from bangerth/more-manifold-documentation

More manifold documentation