Turn on Dopri/Radau tests on Python 3/64-bit

It seems, commit c39de94 fixed #26.
Fix compilers' (gcc, clang) warnings
Do not use sandboxes when collect coverage stats
Run tests in parallel and use boxed subprocesses
Make example Python 3 compatible

[ci skip]
Improved unpickling error message
Fixed import of IsUniqueSeq
Merge branch 'master' of https://github.com/robclewley/pydstool

Conflicts:
	pytest.ini
Test F-A mods for PyCont

Merge branch 'master' of https://github.com/F-A/pydstool into F-A-master
Added message to examples/PyCont_ABReaction.py to show how to use delayed build
Fixed consistency of stdout strings with method names; added rout.stop() before raising runtime error
Merge branch 'F-A-master'
Added option to delay PyCont's build of AUTO DLL module to allow user-defined C code to be added to vector field etc.