Use type traits and features of C++11, then use Boost.MP11.
Remove unused and unnecessary metafunctions in `detail` namespace.
Remove explicit access to ::type as no longer necessary with MP11.
Clean up and reformat code according to the current guidelines.
Legacy tests have been updated where necessary to accommodate
switch to MP11.
Replace std::is_integral with gil::detail::is_channel_integral
Replacing boost::is_integral with std::is_integral is C++ UB:
C++11 / 20.11.2 Header <type_traits> synopsis
1 The behavior of a program that adds specializations for any
of the class templates defined in this subclause is undefined
unless otherwise specified.
Implements also proposal in #93Closes#229
Group include directives, sort within group:
* In headers of GIL core and extensions:
1. boost/gil/extension/*
2. boost/gil/*
3. boost/*
4. C++ standard library headers
* In programs:
1. boost/gil/*
2. boost/*
3. C++ standard library headers
4. "xxx.hpp" for local headers
Add basic guidelines to CONTRIBUTING.md.
Add/Remove #include <boost/config.hpp> or std headers un/necessary.
Rename gil_concept.hpp to concepts.hpp.
Remove gil_all.hpp - we already have all-in-one boost/gil.hpp.
Tidy up and unify copyright and license header.
Tidy up formatting and excessive whitespaces in some comments.
Remove Doxygen block with file description, author, date, etc.
Remove dead or commented pragmas and directives.
Trim trailing whitespaces.
