fix: mistake when given single row matrix

commit 21e5498945046a644d94b783c0fafe2cfbd8be89 in master
fix: memory leak while calling gcd with a term and a non-term poly
new: division and gcd of integer polynomials via factory

added conversion functions between integer polynomials in Singular and Factory
extended the singclap_gcd and singclap_pdivide functions to cover the case where
ground ring is integer
chg: moved all routines for tropical geometry to tropical.cc/.h
new: initialReduction
fix: missing -lcddgmp flag when linking libgfan.so
fix: wrong comment on errors in n_Div for Z
fix: missing return value for procedure
new: pReduce(poly g, const number p)
new: reduceInitially(poly &h, const poly g)
new: reduceInitially(ideal I, const number p)
new: reduceInitially(ideal I, const number p, poly g)
new: initialReduction(ideal I)