fix: mistake when given single row matrix
chg: moved listOfFacets to bbcone.cc where it belongs
chg: various new features

added features for tropical geometry (req by andreas):
- tropical variety of a polynomial
- common refinement of two polyhedral fans
- Polymake::vertexAdjacencyGraph
- Polymake::vertexEdgeGraph

also added various features for polytopes which were already available for cones, changed documentation accordingly
Merge pull request #346 from YueRen/gfanlib

Gfanlib
fix: by gpfister: extractZ
chg: 3-1-7
fix: removed fix path for xv
chg: deleted unneccessary swap
chg: moved some code from .h to .cc
chg: absBiFactorizeMain now also returns other factors
chg: added factorizationWRTDifferentSecondVars to header
chg: removed trailing spaces
chg: added decompress for absolute factors
chg: renamed facAbsFact.* to facAbsBiFact.*
chg: changes due to renaming
fix: compiler warnings about empty if
added: new absolute factorization for multivariate polys
chg: changes due to new abs factorization
chg: changes to build system and Singular interface due to new routines
chg: added more tests from absfact.lib to absbifact.tst
fix: includes and some typos
chg: fewer bivariate factorizations and removed  unnecessary test