Fix const in apply_on_tuple
Fixed bug out of domain for mesh with positive and negative matsubara frequencies
gf: imfreq: fix out of bound product gf imfreq

- gf<cartesian_product<imfreq,imfreq>> was not correct
  when out bounds. Fixed evaluator.
- tensor_proxy : fix the trait for algebra which was incorrect.
- TODO: clean code (repetition, put in mesh some windowing).
gf: imfreq. general case, fix python interface

- Fix constructor, now taking n_points like the positive_only case
- Fix python, h5read, for general case (i.e. all frequencies).
shared_ptr<void> can not be constructed directly in c++14

- Fix for compilation on clang 3.4 in c++1y mode.
Put back the check of compiler version commented for unknown reasons...

Probably a mistake ....
continued : further correction on mac

The issue was the detection of clang version on mac,
depends if packaged by Apple or not...
add one speed test ...

machine dependant, to get an idea...
gf : target_shape_t. change size_t to int

- to avoid narrowing pbs.
- otherwise {n,n}, with n int does not work, which is crazy.
small change in clang-format config.
add trace for ImmutableMatrix