mostly eliminate Eigen in the FIP and VFP code
this code mostly used the Eigen vectors as arrays anyway, so let's use `std::vector`.
also, this patch only "mostly eliminates" Eigen from from these parts of the code because the source files of the VFP code still use AutoDiffBlock; Unfortunately this cannot easily be changed because `flow_legacy` depends on these methods. (`flow_ebos` does not use the incriminating methods.)
with travis being happy, let's also harass jenkins: