cmake: http://www.cmake.org (Version 3.2 or better)
Ipopt: https://projects.coin-or.org/Ipopt
Bonmin: https://projects.coin-or.org/Bonmin
Gurobi: http://www.gurobi.com
Cplex: https://www-01.ibm.com/software/commerce/optimization/cplex-optimizer/
Mosek: https://www.mosek.com
Just enter
cmake ..
make
The Gravity binaries will then appear under Gravity/bin.