result of pow_abs(inf,x) was incorrect : always nan, in scalar and simd
extreme value distribution and its unit tests
missing includes in as_terminal.hpp
normstat.cpp was suppressed in Cmakelist by mistake
Intel compiler fixes following dispatch refactor
Merge pull request #873 from jtlap/pow_abs_pb

result of pow_abs(inf,x) was incorrect : always nan, in scalar and simd
Merge pull request #876 from jtlap/ev_statistics

extreme value distribution and its unit tests
adjusting ulp threshold for evpdf
adjusting ulp threshold for evcdf
missing typedef in static_fft
fix warnings in static_fft when SIMD is disabled
Introduce is_safe free function.

is_safe was a member function on some of NT2 sequence like
types that made difficult the use of alternate types from
3rd party as such a component.

Contents of this commit :
 - factorize is_safe as a free function
 - remove ::is_safe from the interface of container/buffer types
 - Amend test and usage
raw() is now data()

Still in the process of alignign our API with std containers one,
raw() now becomes data() to follwo C++11 API style. Similarly, the
free function raw() is also renamed data().
along can be used as LHS
Remove dummy value from buffer.
Move assign_swap to core/utility
Rationalize swap on different terminal

Swapping terminals of different layout can't be done without
some copies. Instead of forcing buffer to have a non standard
swap interface, we make nt2::swap handles those cases.
Rename push_back on buffer to append and make it external

container now use append(Sequence,Iterator,Iterator) so
the append API is not tied to any member function.
simd::aligned_array supports size of 0
Remove obsolete array_buffer

container of automatic storage now directly used simd::aligned_array