Merge Gizmo-SPH into the master branch



See merge request !223

Check that the code and ICs have the same dimensionality

Does what it says on the tin. :)

Implementation of #203 following @bvandenbroucke's request. When reading ICs we check whether the ICs have the same dimensionality as the code was compiled with. We assume d=3 by default to retain compatibility with Gadget-[234].

Branch can be removed.

See merge request !221

Allow the users to change the compression rate of datasets.

Compression is switched off by default for performance.

See merge request !220

Removed calls to fminf and fmaxf in the critical sections of the code.

Is there any reason not to do this ? I have replaced calls to `fminf` and `fmaxf` by ternary operators. That leads to massive speed-ups. 

According to vTune, we were spending large amounts of time inside these functions. 

Is there any reason to use them over what I have done ? Any special behaviour of the functions that we would need in some cases ?

See merge request !219

Disk patch

generates glass-like ICs for a disk-patch (gas in vertical hydrostatic equilibrium with external potential). Runs this disk-patch without assuming gas remains isothermal. See readme.txt

See merge request !217

Allow the users to change the compression rate of datasets. Compression is switched off by default for performance.

Made a small but important change in computation of hydro acceleration. Added total energy to snapshots instead of thermal energy.