Realised that if gurobi and glpk isn't installed on the system then we can't compile anything!

GLPK is an easy fix, there is a publically available maven repository, which I've added to the core pom.xml.  The user will still need GLPK installed to use it by phygen will compile just fine with the publically available stub jar.

Gurobi is much harder to deal with.  There is no publically available pom.  To deal with the problems this throws up, I've had to pull out all the gurobi specific code and put it into a separate module (which isn't compiled by default, in order to completely decouple gurobi from the rest of the project.  If the user has gurobi installed, they will need to install the gurobi jar into their maven repo before compiling.  They will also have to uncomment some lines in the phygen pom and the Solver class.  Not an ideal solution!  Also I may have introduced some problems into SuperQ, QNet and the Scaling tool, which all previously required access to gurobi.  This still needs to be checked out.