i/o conversion

Would that work ?

See merge request !201

Bug fixes



See merge request !202

Io unit conversion

This implements two changes:

 - Unit conversion from ICs to internal units and from internal units to snapshots when doing i/o.
 - A much simpler interface to add/remove fields to be written/read during i/o.

Could you let me know whether your usual tests still run with this ? 

See merge request !194

Conflicts:
        src/Makefile.am
	src/parallel_io.c
	src/serial_io.c
	src/single_io.c

Gamma power speed up

"Fix" to #185. See also the discussion in #166.

Two improvements:

 - Speed-up the calculation of x^\gamma, x^{\gamma-1} and x^-(\gamma-1) . Currently support \gamma=5/3, \gamma=4/3 and \gamma=2.
 - Write the details of the hydro scheme in the snapshots.

Branch can be removed.

See merge request !195

This reverts commit 9f311bbc

Macro vectorisation

Created a macro called `WITH_VECTORIZATION` in `config.h` that enables vectorisation throughout the code. Replaced all occurrences of `VECTORIZE` with `WITH_VECTORIZATION` throughout the code. Replaced compiler macros, i.e `__AVX__`,`__MIC__` with platform defined macros: `HAVE_AVX`, `HAVE_AVX512_F`... in `vector.h`.

Added place holders for vectorised versions of force and density interactions for Gadget2 and Minimal SPH schemes. An error will be displayed at runtime if the code is compiled with vectorisation enabled and using either Gadget2 or Minimal SPH schemes.

See merge request !200