Skip interactions, where one of body isClump

It caused segmentation fault during intensive adding/removal
clumps during the simulation.
Fix doc-compilation for IPython >=2
Enable vectorization in eigen3-lib

Together with vectorazation some other flags were
removed:
EIGEN_DONT_VECTORIZE
EIGEN_DONT_ALIGN
EIGEN_DISABLE_UNALIGNED_ARRAY_ASSERT
EIGEN_NO_DEBUG

It should increase the calculation speed of  some
vector-matrixes operations.
Do not use Eigen3 in parallel mode.
Recommend minimal Eigen3 version 3.2.1.

Older Eigen3 versions can lead to instabilities
due to enabled vectorization.
remove old code
improve output and remove first iteration in calculation velocity estimation
add definition for functor order
JCFpm : doc of JCFpmPhys.FnMax precised (minor change). And formulation of kn for onJoint interactions according to JCFpmPhys.crossSection (rather than mean of surfaces) to be consistent with the whole formulation ("major" change : this may impact the results of previous scripts depending on psd and how much the mechanical behaviour of joint is important)
Set minimal required Eigen3 version 3.2.1
Add NOVECTORIZE option

On some old systems vectorization causes crashes.
This option allows to disable it.
Prevent adding liqVol-parameters into VTK-files

for the case, when "liquidcontrol" not enabled.
Fixes crashes in some cases.
Prevent crash in liqVolIterBody

Static function can segfault, if the particle
has no ViscElCapPhys
Disable vectorization by default.

Replace NOVECTORIZE by VECTORIZE. Vectorization segfaults
in some cases. All of them should be fixed.
set number of iterations to be run correctly (thanks Alex)
Doc of VTKRecorder.skipFacetIntr precised so that it better corresponds to code
Extra s in previous commit removed..
Replace Quaternion.Identity by Quaternion((1,0,0),0)

Such constructions in python files are failing when
vectorization is on. Probably because Identity construction
does not return real object (?)
In state pos_set and ori_set use passing by value.

Such construction fails when vectorization is on.
Add addLiqInter function to set liquid "properly"