Correctly read the number of particles when >2^32 in the IC combination script. Also add an option to specify the compression level.

Reduce the number of proxies constructed in the case with gravity

See merge request !673

Parallel rebuild2

Closes #458

See merge request !659

Sorts bug fix

Closes #488

See merge request !676

Fix outputlist test

See merge request !675

somebody forgot empty line, InitialConditions codeblock wasn't showing. Fixed.

See merge request !674

C++ build fix: seems that the file c++config.h undef's the max and min macros, the solution is to include something that pulls in that file before we do our own defines (in minmax.h)

See: https://gcc.gnu.org/ml/libstdc++/2016-01/msg00025.html and #489

Change the task splitting criterion for gravity tasks

Closes #457

See merge request !667