* fix windows build

* wip

* mkldnn seems to build

* address various errors building cpu backend with MSVC

* wip

* wip

* Windows support.

    * Delete dependency of LLVM when building with MSVC.

* Define EIGEN_HAS_CONSTEXPR when using MSVS.

* Fix MSVC build errors.

    * Incorrect argument to 'decltype'. It is VC bug. Work around the
    error with rename the function into different name.

    * MINMAX issue in matmul_bias.cpp.

    * Correct TBB_LINK_LIBS on Windows.

* Fix MSVC link errors.

    1. redefine problems in cpu_builder.obj and convert_layout.obj. It
    is because cpu_builder.hpp contains an implicit implement of
    function runtime::cpu::Builder::build for cpu::op::ConvertLayout.
    The fix is deleting the registration item in cpu_builder.cpp and
    using REGISTER_CPU_OP_BUILDER in convert_layout.cpp.

    2. Fix the dependent libraries path on Windows. It should be *.lib
    not *.dll when linking these libraries.

* Set visibility for CPU backend to fix the MSVC linker error.

    MSVC complain that the .def file exceed the size limitatoin
    when using CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS. All the functions
    with CPU_BACKEND_API are used by unit test or nbench.

* Fix unit test build errors on Windows.

    * backend_unary_elementwise.in.cpp: Use all_close_f to test case
    BACKEDND sqrt

    * cpu_fustion.cpp: Fix 'NUM_STEPS' cannot be implicitly
    captured because no default capture mode has been specified

    * cpu_test.cpp: Use portable setenv and unsetenv from misc.hpp.

    * tools.cpp: Use portable fpopen from misc.hpp.

    * misc.hpp/misc.cpp: Add new files to host misc functions that Linux and
    Windows using different implementation.

* Make Debug mode work with MSVC.

* style

* fix line ending