[freeflow]

- added individual headers for boundary layer and mass transfer models, which were implemented in the couplinglocaloperator

[multidomain]
- uses above mentioned new header and classes
- improved own start function, especially the usage function
- updated parts of the reference solutions, due to marginal deviations

[implicit]
- added convenience function for the viscosity in the 2p2c model 


git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@14743 2fb0f335-1f38-0410-981e-8018bf24f1b0