build: update configure (unix) to accpept python 2.7 too

both python version 2.6, 2.7 are supported, there's little difference:
http://docs.python.org/dev/whatsnew/2.7.html#porting-to-python-2-7
enable python 2.6 / 2.7 in include header files

conditional include on _PY27 defined in configure if python is v2.7
make links for python2.7 -> python2.6 in external/ dir

this enables build with python2.7
not necessary after libs are modular
compile: enable include -I of standard libs

as we'll shift to shared libs, and it does not cause any problems
remove old code workaround (for gcc4.1)

that compiler is 6 years old, I seriously doubt it could be installed on any recent ditribution,
safe to delete this hack
gitignore: remove nonexisting file reference
compiling: replace hard-coded gcc/g++ reference with $CXX

so that compiler found by ./configure can be used
(support for llvm/clang)
build: proper make clean target

recursively call make clean for $subdirs
and call cleanup.sh script (nice if removed later)
and setup.py --clean (dtto)
gcc/clang compatibility fix (lvalue cast)

be more strict, dont allow lvalue casts (clang default, gcc does allow it)
gcc/clang: fix function declaration after all templates defined

just reorder some template/function definitions, so that all templates required are already defined (above)
see http://clang.llvm.org/compatibility.html#dep_lookup
small fix: if-else not needed, always include

the #include is used in both cases
gcc/clang: fix template lookup

this is for adhesing to C++ coding standards,
fix unknown operator<<  ...
see http://clang.llvm.org/compatibility.html#dep_lookup
fix provided by placing a declaration (of operator<< template) before the function which
uses it.
python 2.7: update readme for python 2.7 support
Merge pull request #89 from breznak/compilation

Compilation
update boost to 1.52.0

need more recent version for compiler fixes/warnings, fixes, portability and other improvements
as of today, 1.53.0 is the latest version, but 1.52 is latest that builds without any modifications to the code.
Changelog can be found here: http://www.boost.org/users/history/
Merge branch 'master' into python27-support
Revert "build: proper make clean target"

This reverts commit 8a991fd6f5649e422c3d62632bfc878a557e2bc8.
Merge pull request #113 from scottpurdy/master

Revert breaking commit
Merge branch 'master' into python27-support
Merge pull request #85 from breznak/python27-support

Python27 support