Resolve "missing periodic intersection volume function for AABBs"

Closes #56

See merge request walberla/walberla!104

[API] changed return type to std array for improved usability

See merge request walberla/walberla!101

Mesh init

See merge request walberla/walberla!99

Replace deprecated -openmp flag in Intel 17 compiler

Closes #15

See merge request walberla/walberla!1

[API] Use ParserUBB in ExtendedBoundaryHandlingFactory

See merge request walberla/walberla!94

Refinement support for BoundaryFromDomainBorder

See merge request walberla/walberla!95

BoundarySetter should only call Boundary::createConfiguration once

See merge request walberla/walberla!97

Resolve "There are "gaps" created by the SFC partitionier"

Closes #54

See merge request walberla/walberla!96

- NearestNeighborFieldInterpolator::get needs to break out of all loops, just not the current one. While the test seemed to succeed anyway, it crashed with corrupted memory during exit when compiled with Intel 17 in Release mode.
- FftTest should not use thread-unsafe RNG in parallel section. Otherwise the Intel 16 compiler crashes.
- Revert to -openmp on Intel < 16.0.3, which crashes while processing some of our OpenMP loops (e.g. BoundaryHandling::treatDirection).

Also adds OpenMP support for macOS (requires Xcode 7.0, CMake 3.12 and separate libomp from MacPorts/Homebrew)

UBB boundary with equation parser

See merge request walberla/walberla!93

Add createConfiguration functions to pe_coupling boundaries

See merge request walberla/walberla!92

While it makes no sense to create these boundary types from a config file, geometry::initBoundaryHandling needs this function to be present for all boundary types in the boundary handling.

was only a debug check

this should be the common case