update for xcode 5.1.1

- clang 3.4 on default Os X.
- automatically in C++14 mode.
- a little fix in clef (var >> ...) because of an apparent bug in auto
  detection in clang.
magic : redirect std::cout to python sys.out.write

- for all functions, except when GIL option (not implemented) is here
  we use a triqs::py_stream, which redirect the stream
  to python sys.write
- so that a simple C++ code with a std::cout
  print its output in the notebook...
- NB : it only works for the code within the cell.
  If it calls another function on the lib which uses cout,
  print is not redirected.
  Designed for simple tests....
- cerr not (yet) redirected. (useful ?).
pytream  : add pragma to remove warning

- usual char * in python
Fix import array in extensions.

- import arrays in extensions (mako file).
- put import_arrays in converter,
  along the lines of our own objects (numpy and triqs uses
  the same capsule technique, i.e. the standard technique from python
  doc.)
Make it compile again in pure C mode
Silence some gcc warnings...

- Silence some trivial warning.
- TODO: narrowing in a few places.
Correction of f273c09c6f024e

- a missing include...
C14 : add sequence.

correct seq gcc code inclusion
Fix #85 : narrowing conversion
tuple tools : simplify

- simplify implementation of several functions.
- clean API, rename, etc...
- add more documentation
hdf5 : clean up

- For users : only change is :
   H5::H5File in apps. to be replaced by triqs::h5::file, same API.
- using only the C API because :
   - it is cleaner, better documented, more examples.
   - it is the native hdf5 interface.
   - simplify the installation e.g. on mac. Indeed, hdf5 is
     usually installed without C++ interface, which is optional.
     E.g. EPD et al., brew by default.
- clean the notion of parent of a group. Not needed, better iterate
  function in C API.
- modified doc : no need for C++ bindings any more.
- modified cmake to avoid requiring CPP bindings.
first draft of mpi