a new try on vectorization of CL kernels.
Merge branch 'feature/clext' into feature/new_clext
Merge branch 'feature/clext' into feature/new_clext
bug fix and some minor improvements.
Merge branch 'dev' into feature/clext
Merge branch 'dev' into feature/clext
Merge branch 'dev' into feature/clext
more work on vectorization of CL kernels.
more work on vectorization of CL kernels (II).
more work on vectorization of CL kernels (III).
more work on vectorization of CL kernels (IV).
Kepler solver: more improvements and bug fixes.
more improvements on Kepler solver: hopefully it is fast enough now.
Kepler solver: reduces effect of round-off error, bug fixes and minor improvements.
make implementation of CL kernels simpler.
minor changes.
Kepler solver: minor changes.
more work on vectorization of CL kernels (V).
Kepler solver: improved treatment for softening > 0.
Kepler solver: little modification on the orbital period formula.