Bump version to 2.4.0

Fix staging shared tests

v2.4.0 docs and ReadMe bumps

fix #1541 Iotest return fix 

fix HDF5Reader build with MSVC

moving all readthedocs requirements to conda

including pip sphinx packages
readthedocs can pick the adios2 conda python module

I should have gotten them all now via `-Werror=vla` (with clang)

including use of `uint` and more stack-allocated arrays

Sadly, variable-sized stack arrays are only a feature of C99, but not C++11,
so this patch uses std::vector instead.

Conda environment in rtd

fix MSVC/conda build (resubmit #1575)

Kai Germaschewski authored 5 years ago and Podhorszki, Norbert committed 5 years ago

This simply renames `helper::CopyMemory` to `helper::CopyMemoryBlock` to
avoid a name clash with the `CopyMemory` defined in the MSVC build in #1485.

(cherry picked from commit 5f9bdb4e42a108ec19c2bf4034a3a2ddb0c5d951)

Trying to pull Python module for API docs in readthedocs

Germasch bpls warnings

- Handle LocalValueDim (local values turned into 1D global array) in …

Merge branch 'pr/bpls_warnings' of https://github.com/germasch/ADIOS2 into germasch-pr/bpls_warnings

* 'pr/bpls_warnings' of https://github.com/germasch/ADIOS2:
  bpls: fix some warnings for size_t printf arguments

- Do not write values in characteristics in the Data buffer (like it was in adios 1.x BP3)
- Do write LocalValueDim (local value at writing) variable value after metadata (like other values)
- Print payload of single value variables in data

Refactored and added docs contents

- Add header to all BP4 data files, metadata files and index table

%PRIu64 is for uint64_t, %zu is for size_t, which on the Mac (and 32-bit
archs) aren't aliases.

Report the availability of RDMA for Staging in CMake summary

- Modify header content:
  - 32 bytes Tag string e.g. "ADIOS-BP v2.3.1 Index Table     "
  - byte 36 endianness
  - byte 37 BP version
  - byte 38 Active flag (in Index table it indicates active writer)
- bp4dbg print header for all files
- bp4dbg just seeks over real data instead of reading it

  fix a potential problem in WriteCollectiveMetadataFile() function
  clang format
  fix the bug in doclose function for BP4 engine

Test HDF5 with simple tests

Additional documentation improvements.

* release: