B-tree library for eventual proposal to Boost

THIS IS AN BETA LIBRARY STILL UNDER DEVELOPMENT.
IT IS SHOULD ONLY BE USED BY THOSE WILLING TO TAKE THE RISKS
INHERENT WITH BETA LEVEL SOFTWARE.

To experiment with the library, various other boost libraries must be
available. Below is one way to create such a setup.

Note: If you don't want use SSL to connect to GitHub,
replace "git@github.com:" with "https://github.com/". 

Note: Install Subversion, Git, and a C++ compiler first if you haven't
already done so.  Be sure there is a "user-config.jam" file in your
home directory and it is set up for your compiler (or compilers).

Windows:
  cd where-you-want-stuff-to-go
  svn export http://svn.boost.org/svn/boost/trunk boost-trunk trunk-ex
  cd trunk-ex\libs
  git clone git@github.com:Beman/endian.git endian
  git clone git@github.com:Beman/btree.git btree
  cd ..\boost
  mklink /d endian ..\libs\btree\include\boost\endian
  mklink /d btree ..\libs\btree\include\boost\btree
  
POSIX-like systems:
  sudo apt-get install libbz2-dev
  cd where-you-want-stuff-to-go
  svn export http://svn.boost.org/svn/boost/trunk boost-trunk trunk-ex
  cd trunk-ex/libs
  git clone git@github.com:Beman/endian.git endian
  git clone git@github.com:Beman/btree.git btree
  cd ../boost
  ln -s ../libs/endian/include/boost/endian endian
  ln -s ../libs/btree/include/boost/btree btree
  
As a confidence test, the following should build b2, build various
libraries and then run the btree regression tests, which should all
report "**passed**".

Windows:
  cd trunk-ex
  .\bootstrap
  .\b2
  cd libs\btree\test
  ..\..\..\b2

POSIX-like systems:
  cd trunk-ex
  ./bootstrap.sh
  ./b2
  cd libs/btree/test
  ../../../b2
  
----------------------------------------------------------------------

Notes for using Visual Studio  

A Windows Visual Studio solution is included:  btree\test\msvc2012\btree.sln
Be sure to do the following setup before starting Visual Studio.

IMPORTANT: If Preprocessor macros are supplied via a common property page,
<inherit from parent or project defaults> must be set for each project!

Setup Windows to use the solution:
  
  set BOOST_TRUNK=boost-root-path
  path %path%;%BOOST_TRUNK%\stage\lib  
  cd %BOOST_TRUNK%
  .\bootstrap
  .\b2 --with-system --with-chrono --with-timer --with-filesystem --with-iostreams link=shared address-model=64 variant=debug toolset=msvc-11.0express
To find out more about builds:

  cd boost-root
  .\b2 --help
  
------------------------------------------------------------------------------------------
Copyright Beman Dawes, 2013
Distributed under the Boost Software License, Version 1.0.
See http://www.boost.org/LICENSE_1_0.txt