Add checks for OpenMP FFTW when pthread version is not found

Closes #831

See merge request !1672

Re-organised the creation of the RT-specific time-step tasks on foreign cells to avoid duplicates

See merge request !1685

RTD updates

Closes #839

See merge request !1682

Import fixes to parameter files for low-z EAGLE examples from the no_marktasks branch. Also adds an EAGLE-12 RT example

Add missing task types to the gathering of weights in the partition code

See merge request !1684

Import a few doxygen fixes, small changes to FOF, and debugging checks from the branch pack_foreign_gpart

Reduce the recording window to a smaller value if it the delta to the next snapshot is shorter than the desired recording time

The invert_table() function in cosmology.c should not be defined if we don't have libgsl

See merge request !1683

RT: allow flexible  number of sub-cycles determined by local conditions

See merge request !1660

fix #840

Closes #840

See merge request !1681

Allow space replication and id remapping for neutrino particles

Closes #837

See merge request !1673

Updating xray tables

See merge request !1680

Avoid buffer overflow when computing comoving distance inverse table

Closes #838

See merge request !1677

Issues found by sanitizer

See merge request !1676

Fix lightcone neutrino mass maps

Closes #827

See merge request !1644